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Journal Article•DOI•

The global energy balance from a surface perspective

Martin Wild1, Doris Folini1, Christoph Schär1, Norman G. Loeb2, Ellsworth G. Dutton3, Gert König-Langlo •
ETH Zurich1, Langley Research Center2, National Oceanic and Atmospheric Administration3
01 Jun 2013-Climate Dynamics (Springer-Verlag)-Vol. 40, Iss: 11, pp 3107-3134
TL;DR: In this article, the authors make extensive use of the growing number of surface observations to constrain the global energy balance not only from space, but also from the surface, and combine these observations with the latest modeling efforts performed for the 5th IPCC assessment report to infer best estimates for the global mean surface radiative components.
Abstract: In the framework of the global energy balance, the radiative energy exchanges between Sun, Earth and space are now accurately quantified from new satellite missions. Much less is known about the magnitude of the energy flows within the climate system and at the Earth surface, which cannot be directly measured by satellites. In addition to satellite observations, here we make extensive use of the growing number of surface observations to constrain the global energy balance not only from space, but also from the surface. We combine these observations with the latest modeling efforts performed for the 5th IPCC assessment report to infer best estimates for the global mean surface radiative components. Our analyses favor global mean downward surface solar and thermal radiation values near 185 and 342 Wm−2, respectively, which are most compatible with surface observations. Combined with an estimated surface absorbed solar radiation and thermal emission of 161 and 397 Wm−2, respectively, this leaves 106 Wm−2 of surface net radiation available globally for distribution amongst the non-radiative surface energy balance components. The climate models overestimate the downward solar and underestimate the downward thermal radiation, thereby simulating nevertheless an adequate global mean surface net radiation by error compensation. This also suggests that, globally, the simulated surface sensible and latent heat fluxes, around 20 and 85 Wm−2 on average, state realistic values. The findings of this study are compiled into a new global energy balance diagram, which may be able to reconcile currently disputed inconsistencies between energy and water cycle estimates.

Summary (3 min read)

Jump to: [1 Introduction] – [2 Observational data] – [3 Model data] – [4 Assessment with direct observations] – [4.2.1 Solar radiation] – [4.2.2 Thermal radiation] – [5 Discussion of Earth’s global mean energy balance] and [6 Concluding remarks]

1 Introduction

  • The genesis and evolution of Earth’s climate is largely regulated by the global energy balance and its spatial and temporal variations.
  • Substantial uncertainties exist in the quantification of its different components, and its representation in climate models, as pointed out M. Wild (&) D. Folini C. Schär Institute for Atmospheric and Climate Science, ETH Zurich, Universitätsstr.
  • Uncertainties in the components of the surface radiation budget are thus generally larger and less well quantified than at the TOA.
  • In the present study, the authors do not only rely on satellite observations, but make extensive use of the information contained in radiation measurements taken from the Earth surface, to provide direct observational constraints also for the surface fluxes.

2 Observational data

  • The satellite observations used in this study to constrain the net fluxes at the TOA stem from the CERES mission that measures filtered radiances in the solar (0.3 and 5 lm), total (0.3 and 200 lm), and window (8 and 12 lm) regions (Wielicki et al. 1996).
  • A subset of 760 GEBA sites, which provide multiyear records and allow the construction of representative solar radiation climatologies, was used in the present study.
  • BSRN provides radiation measurements with high accuracy and temporal resolution (minute data) at a limited number of sites in various climate zones.
  • Datasets from both measurement methods are used in this study.

3 Model data

  • The authors make use of general circulation model (GCM) generated data that have been compiled in the framework known as CMIP5 (5th phase of the Coupled Model Intercomparison Project).
  • The authors analyzed the last 2 decades of these experiments (1985–2004) which are completely covered by all participating models.
  • This period can be considered as representative for present day climate conditions and is long enough to generate stable climatological means.
  • Therefore, the authors only consider one ensemble realization of each model in the following analyses.
  • In addition to the CMIP5 models, surface radiative fluxes as estimated in the reanalysis from the European Centre for Medium-Range Weather Forecasts covering the period 1958–2002 (ERA40, Uppala et al. 2005) are considered in this study.

4 Assessment with direct observations

  • As mentioned in the introduction, the TOA radiative flux exchanges are now known with unprecedented accuracy from recent satellite programs such as CERES and SORCE.
  • Wm-2, respectively, with a standard deviation of 3.0 Wm-2 (Table 3) and is well within the observational uncertainty range.
  • A slightly lower planetary imbalance of 0.58 Wm-2 is obtained by Hansen et al. (2011) for the same period, if the Levitus et al. (2009) upper ocean heat uptake estimate is used instead.
  • The 2-sigma uncertainty range for the global mean thermal outgoing radiation therefore spans from about 236–242 Wm-2.
  • Overall, there is no evidence for substantial systematic model biases in the TOA net flux exchanges in the CMIP5 models relative to CERES on a global mean basis.

4.2.1 Solar radiation

  • Global mean values of downward solar radiation at Earth’s surface as calculated in the CMIP5 models are shown in Fig.
  • In this Figure, the displayed biases are averages over the model biases at sites located within common latitudinal belts of 5 .
  • The model-calculated downward solar radiation biases compared to these observations are shown in Fig. 9 at the 38 individual BSRN sites.
  • At individual sites, the differences in the long-term annual means measured with the two measurement methods are within a few Wm-2.
  • To obtain a best estimate for the globally averaged downward solar radiation, the associated biases of the individual models and ERA40 are related to their Fig.
  • 5 Global annual mean downward solar radiation at Earth’s surface under present day climate calculated by 22 CMIP5/IPCC AR5 models as listed in Table 2.

4.2.2 Thermal radiation

  • In the CMIP5 GCMs, the net thermal budgets at the surface and in the atmosphere show larger discrepancies than at the TOA, as can be inferred from Fig. 4 and Table 3.
  • The surface thermal budget consists of the downward and upward flux components.
  • Annual multimodel mean downward thermal radiation biases at the 41 individual BSRN sites are shown in Fig. 16.
  • To obtain a best estimate for the global mean downward thermal radiation in the same way as before for the downward solar radiation, the authors again relate the model and ERA40 biases to their respective global mean values.
  • A very distinct relationship can be noted between the model biases and their global mean values, with a correlation of 0.94 (Fig. 18).

5 Discussion of Earth’s global mean energy balance

  • Along with an evaluation of the radiation budgets in the latest generation of global climate models, the above analysis aimed at providing best estimates for the global mean surface radiative fluxes, using direct surface observations as constraints.
  • Such uncertainty information is lacking in most of the published global energy balance diagrams.
  • The associated uncertainty range in Fig. 1 from 394 to 400 Wm-2 covers all major published values as well as most CMIP5 models.
  • Together with the best estimate for the surface absorbed solar radiation of 161 Wm-2 in Fig. 1, this results in a best estimate of 106 Wm-2 for the global mean surface net radiation.

6 Concluding remarks

  • In this study the authors discussed the global mean energy balance and its representation in the CMIP5 climate models using as much as possible direct observational references from surface stations and space-born platforms.
  • The combination of newly updated observational records and the latest modeling efforts underway for IPCC AR5 allowed us to infer new estimates for the global mean downward surface solar and thermal radiation, which fit best to the surface observations.
  • The authors are grateful to Prof. Atsumu Ohmura for numerous discussions and for his leadership in the establishment of GEBA and BSRN.
  • The authors dedicate this study to their dear friend and colleague Ellsworth G. Dutton, who passed away the day this paper was accepted.

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ETH Library
The global energy balance from a
surface perspective
Journal Article
Author(s):
Wild, Martin; Folini, Doris; Schär, Christoph; Loeb, Norman; Dutton, Ellsworth G.; König-Langlo, Gert
Publication date:
2013-06
Permanent link:
https://doi.org/10.3929/ethz-b-000058556
Rights / license:
In Copyright - Non-Commercial Use Permitted
Originally published in:
Climate Dynamics 40, https://doi.org/10.1007/s00382-012-1569-8
This page was generated automatically upon download from the ETH Zurich Research Collection.
For more information, please consult the Terms of use.
The global energy balance from a surface perspective
Martin Wild
•
Doris Folini
•
Christoph Scha
¨
r
•
Norman Loeb
•
Ellsworth G. Dutton
•
Gert Ko
¨
nig-Langlo
Received: 31 July 2012 / Accepted: 12 October 2012 / Published online: 13 November 2012
Ó Springer-Verlag Berlin Heidelberg 2012
Abstract In the framework of the global energy balance,
the radiative energy exchanges between Sun, Earth and
space are now accurately quantified from new satellite
missions. Much less is known about the magnitude of the
energy flows within the climate system and at the Earth
surface, which cannot be directly measured by satellites. In
addition to satellite observations, here we make extensive
use of the growing number of surface observations to
constrain the global energy balance not only from space,
but also from the surface. We combine these observations
with the latest modeling efforts performed for the 5th IPCC
assessment report to infer best estimates for the global
mean surface radiative components. Our analyses favor
global mean downward surface solar and thermal radiation
values near 185 and 342 Wm
-2
, respectively, which are
most compatible with surface observations. Combined with
an estimated surface absorbed solar radiation and thermal
emission of 161 and 397 Wm
-2
, respectively, this leaves
106 Wm
-2
of surface net radiation available globally for
distribution amongst the non-radiative surface energy
balance components. The climate models overestimate the
downward solar and underestimate the downward thermal
radiation, thereby simulating nevertheless an adequate
global mean surface net radiation by error compensation.
This also suggests that, globally, the simulated surface
sensible and latent heat fluxes, around 20 and 85 Wm
-2
on
average, state realistic values. The findings of this study are
compiled into a new global energy balance diagram, which
may be able to reconcile currently disputed inconsistencies
between energy and water cycle estimates.
Keywords Earth Radiation Budget Surface energy
balance Global climate models Global energy balance
Surface/Satellite observations CMIP5/IPCC-AR5
model evaluation
1 Introduction
The genesis and evolution of Earth’s climate is largely reg-
ulated by the global energy balance and its spatial and tem-
poral variations. Anthropogenic climate change is, from a
physical point of view, first of all a perturbation of the energy
balance of the globe, through the modification of the atmo-
spheric composition of greenhouse gases and aerosols.
Variations in the global energy balance affect not only the
thermal conditions on the planet, but also various other cli-
mate elements, such as atmospheric and oceanic circula-
tions, the components of the hydrological cycle, glaciers,
plant productivity, and terrestrial carbon uptake (e.g.,
Ramanathan et al. 2001; Ohmura et al. 2007; Mercado et al.
2009; Wild et al. 2008). Despite the central role of the global
energy balance in the climate system, substantial uncer-
tainties exist in the quantification of its different compo-
nents, and its representation in climate models, as pointed out
M. Wild (&) D. Folini C. Scha
¨
r
Institute for Atmospheric and Climate Science, ETH Zurich,
Universita
¨
tsstr. 16, 8092 Zurich, Switzerland
e-mail: martin.wild@env.ethz.ch
N. Loeb
NASA Langley Research Center, 21 Langley Boulevard,
Hampton, VA 23681-2199, USA
E. G. Dutton
NOAA/ESRL, R/GMD, 325 Broadway, Boulder,
CO 80305, USA
G. Ko
¨
nig-Langlo
Alfred Wegener Institute, Bussestrasse 24,
27570 Bremerhaven, Germany
123
Clim Dyn (2013) 40:3107–3134
DOI 10.1007/s00382-012-1569-8
in numerous studies published over the past decades (e.g.,
Hartmann and Short 1980; Hartmann et al. 1986; Ramana-
than et al. 1989; Gutowski et al. 1991; Ohmura and Gilgen
1993; Pinker et al. 1995; Li et al. 1997; Gleckler and Weare
1997; Kiehl and Trenberth 1997; Wild et al. 1998; Gupta
et al. 1999; Hatzianastassiou and Vardavas 1999; Potter and
Cess 2004; Raschke and Ohmura 2005; Trenberth et al.
2009; Trager-Chatterjee et al. 2010; Ohmura 2012; Qian
et al. 2012; Wild 2012; Stephens et al. 2012a, b). This
becomes also evident when comparing different schematic
diagrams of the global energy balance published in text
books or in the peer-reviewed literature, which often vary
greatly in the numbers given therein representing the mag-
nitudes of these energy flows in terms of global means (e.g.,
Kiehl and Trenberth 1997; Trenberth et al. 2009; Wild et al.
1998; Raschke and Ohmura 2005; Wild 2012; Stephens et al.
2012b). A representation of such an energy balance diagram
is given in Fig. 1 and will be discussed in more detail in this
study.
Knowledge on the energy exchange between Sun, Earth
and space has recently been improved through new satellite
missions such as the Clouds and the Earth’s Radiant Energy
System (CERES, Wielicki et al. 1996) and the Solar
Radiation and Climate Experiment (SORCE, Anderson and
Cahalan 2005). These allow the determination of the top of
atmosphere (TOA) radiative flux exchanges with unprece-
dented accuracy (Loeb et al. 2012).
Much less is known, however, about the energy distri-
bution within the climate system and at the Earth surface.
Unlike the fluxes at the TOA, the surface fluxes cannot be
directly measured by satellites. Instead, they have to be
inferred from the measurable TOA radiances using
empirical or physical models to account for atmospheric
attenuation and emission, which introduces additional
uncertainties. Uncertainties in the components of the sur-
face radiation budget are thus generally larger and less well
quantified than at the TOA. Debated are, for example, the
partitioning of solar energy absorption between the atmo-
sphere and surface, as well as the determination of the
thermal energy exchanges at the surface/atmosphere
interface (e.g., Raschke and Ohmura 2005; Wild 2008,
2012; Trenberth et al. 2009
; Stephens et al. 2012b).
In the present study, we do not only rely on satellite
observations, but make extensive use of the information
contained in radiation measurements taken from the Earth
surface, to provide direct observational constraints also for
the surface fluxes. Such observations become increasingly
available from ground-based radiation networks (Sect. 2).
We use these observations to assess the radiation budgets as
simulated in the latest modeling efforts performed within
Fig. 1 Schematic diagram of the global mean energy balance of the
Earth. Numbers indicate best estimates for the magnitudes of the
globally averaged energy balance components together with their
uncertainty ranges, representing present day climate conditions at the
beginning of the twenty first century. Estimates and uncertainty
ranges based on discussion in Sect. 5. Units Wm
-2
3108 M. Wild et al.
123
the Coupled Model Intercomparison Project Phase 5
(CMIP5) for the upcoming 5th IPCC assessment report
(IPCC-AR5) (Sects. 3, 4). We further combine the surface
observations with these models to infer best estimates of the
global mean surface radiative components (Sect. 4). The
outcome of this study is used to discuss a new global energy
balance diagram (Fig. 1), which incorporates the best esti-
mates for the surface energy flux components derived here
along with recent best estimates for the TOA flux compo-
nents (Sect. 5). Conclusions are drawn in Sect. 6.
2 Observational data
The satellite observations used in this study to constrain the
net fluxes at the TOA stem from the CERES mission that
measures filtered radiances in the solar (0.3 and 5 lm),
total (0.3 and 200 lm), and window (8 and 12 lm) regions
(Wielicki et al. 1996). Since there is no thermal channel on
CERES, thermal daytime radiances are determined from
the difference between the total and solar channel radi-
ances. The global mean estimates for the components of
the TOA radiation budget are based on the energy balanced
and filled (EBAF) data set for the period 2001–2010 as part
of the CERES mission, version EBAF 2.6r (Loeb et al.
2012). This data set adjusts the solar and thermal TOA
fluxes within their range of uncertainty to be consistent
with independent estimates of the global heating rate based
upon in situ ocean observations (Loeb et al. 2009).
The surface observations to constrain the surface radia-
tive fluxes are retrieved from two data sources: The global
energy balance archive (GEBA, Gilgen et al. 1998; Ohmura
et al. 1989) and the database of the Baseline Surface Radi-
ation Network (BSRN, Ohmura et al. 1998). GEBA is a
database for the worldwide measured energy fluxes at the
Earth’s surface and currently contains 2,500 stations with
450,000 monthly mean values of various surface energy
balance components. GEBA is maintained at ETH Zurich.
By far the most widely measured quantity is the solar
radiation incident at the Earth’s surface, also known as
global radiation, and referred to as downward solar radiation
in the following. Gilgen et al. (1998) estimated the relative
random error (root mean square error/mean) of the down-
ward solar radiation values in GEBA at 5 % for the monthly
means and 2 % for yearly means. A subset of 760 GEBA
sites, which provide multiyear records and allow the con-
struction of representative solar radiation climatologies, was
used in the present study. This dataset has been used in
previous studies for climate model validation and therefore
allows a comparison of the performance of the latest models
in the present study with older model versions which use the
same observational reference (e.g., Wild 2008). Further, a
small set of records of downward thermal radiation is con-
tained in GEBA, which is also used in this study.
BSRN provides radiation measurements with high
accuracy and temporal resolution (minute data) at a limited
number of sites in various climate zones. First BSRN sites
became operational in the early 1990s. To date more than
50 anchor sites in various climate regimes have reported
their data to the BSRN Archive at the Alfred Wegener
Institute (AWI) (http://www.bsrn.awi.de/). The accuracy of
downward thermal radiation measurements, carried out
with pyrgeometers, is near 3–4 Wm
-2
according to Phil-
ipona et al. (2001) and Marty et al. (2003), thereby meeting
BSRN standards established by Ohmura et al. (1998). The
downward shortwave radiation at the BSRN sites is
required to be measured both as a single total flux mea-
surement with a pyranometer and as component sum of
separate measurements of the direct shortwave flux (mea-
sured with a pyrheliometer) and the diffuse shortwave flux
(measured with a shaded pyranometer). A pyranometer
measures the total incoming solar radiation in the wave-
lengths between 0.3 and 2.8 lm. Datasets from both
measurement methods are used in this study. Some pyra-
nometers used are known to have instantaneous accuracy
limitations of 3–5 % of the full signal due to cosine
response and thermal offset errors combined with other
sources of uncertainty. However, using single pyranome-
ters in conjunction with the component sum method at
BSRN sites (Michalsky et al. 1999), and considering long
term averaging, an accuracy near 5 Wm
-2
(*2 % for 24-h
mean solar irradiance) has been achieved, meeting the
BSRN specifications under optimal observing conditions.
The enhanced accuracy of the component sum is supported
by recent work (Michalsky et al. 2011) that demonstrated
typical operational pyrheliometer measurement instanta-
neous accuracy to be 0.7–1.3 % (95 % confidence level)
and by earlier work (Michalsky et al. 2007), demonstrating
the instantaneous accuracy of near-zero-offset pyranome-
ters to be better than 2–4 Wm
-2
when used for diffuse
(shaded) solar measurements (note that instantaneous solar
irradiance measurement uncertainties in terms of Wm
-2
are reduced, typically by about a factor of 2, when using
24-h or longer averaging). All BSRN solar measurements
are referenced to the World Radiation Reference (WRR)
scale (Frohlich 1991) and as subsequently maintained at
the World Radiation Center, Davos, Switzerland, consid-
ered to be accurate to within 0.3 % and has demonstrated
stability to better than 0.01 % over the past three and half
decades. The WRR is based on a group of absolute cavity
radiometers of similar to identical design as those used to
initially establish the consensus nominal solar ‘‘constant’’
of 1,365 Wm
-2
. Therefore, to make the BSRN measure-
ments consistent with models and other analysis using a
The global energy balance 3109
123
new solar constant of 1,360.8 Wm
-2
requires lowering the
BSRN reported surface solar irradiance values by 0.3 %.
Out of the 50 BSRN sites, more than 40 sites already
provide multiyear records which allow a determination of
representative radiation climatologies. They cover at least a
portion of the BSRN period 1992–2011, and thus can be
considered as representing present-day climate conditions
around the turn of the century. For the present study we
were able to use pyranometer records from 42 stations,
combined pyrheliometer and shaded pyranometer records
from 38 stations, and pyrgeometer data from 41 stations.
Due to the necessity to track the sun with the pyrheliometer
and the shading disk, data gaps in the direct and diffuse
records are typically more frequent than with the pyra-
nometer measurements, which explains the slightly lower
number of stations available for climatologies based on
combined direct and diffuse measurements. A list of the
BSRN stations used in this study is given in Table 1. The
geographical distribution of the GEBA and BSRN sites
used in this study is displayed in Fig. 2.
Monthly mean values were calculated from the BSRN
minute raw data as described in Roesch et al. (2011), by
determining for each month first a mean monthly diurnal
cycle from the raw data gathered into 15-min bins, and then
averaging over the 24 h’ cycle to obtain a monthly mean.
This method minimizes the risk of biases in monthly means
calculated from incomplete data records.
3 Model data
We make use of general circulation model (GCM) generated
data that have been compiled in the framework known as
CMIP5 (5th phase of the Coupled Model Intercomparison
Project). These data have been organized by the Program for
Climate Model Diagnosis and Intercomparison (PCMDI) for
the 5th IPCC assessment report. We focus on the ‘‘historical’’
experiments therein. These experiments were aimed at
reproducing the climate evolution of the twentieth century as
accurately as possible, by considering all major natural and
anthropogenic forcings, such as changes in atmospheric
greenhouse gases, aerosol loadings (tropospheric and
stratospheric volcanic), solar output, and land use. These
experiments are therefore best suited for the assessment of
the capability of the models to reproduce the global energy
balance as accurately as possible. Most experiments start
around 1860 and are carried out up to around 2005. We
analyzed the last 2 decades of these experiments
(1985–2004) which are completely covered by all partici-
pating models. This period can be considered as represen-
tative for present day climate conditions and is long enough
to generate stable climatological means. We also tested our
analyses with differing start and end years, but found the
results presented in this study insensitive to the choice of the
period. This is also understandable given the lack of decadal
variations in the surface radiative fluxes calculated in the
models (Wild and Schmucki 2011). As of June 2012, his-
torical experiments from 22 models were available from
PCMDI for our analyses. These models are listed in Table 2,
together with their respective home institutions. A detailed
description of these models is provided on the web pages of
the PCMDI (http://www-pcmdi.llnl.gov/). Most participat-
ing groups performed multiple simulations of this historic
period with differing initial conditions (ensemble experi-
ments). However, we found that within our analyses, the
choice of a particular ensemble member from a specific
model hardly influenced the results and played a minor role.
Therefore, we only consider one ensemble realization of
each model in the following analyses.
In addition to the CMIP5 models, surface radiative
fluxes as estimated in the reanalysis from the European
Centre for Medium-Range Weather Forecasts (ECMWF)
covering the period 1958–2002 (ERA40, Uppala et al.
2005) are considered in this study. Reanalyses assimilate
the comprehensive worldwide observations from the global
observing system (GOS) into their models. They do not,
however, assimilate the surface radiation observations used
in this study.
4 Assessment with direct observations
4.1 TOA radiation budgets
As mentioned in the introduction, the TOA radiative flux
exchanges are now known with unprecedented accuracy
from recent satellite programs such as CERES and SORCE.
The total solar irradiance (TSI) incident at the TOA, based
on the most recently launched SORCE Total Irradiance
Monitor (TIM), is determined at 1360.8 ± 0.5 Wm
–2
(annual mean), with reported uncertainties as low as
0.035 % (Kopp et al. 2005; Kopp and Lean 2011). This
value is lower than previous estimates, which were around
1,365 Wm
-2
(Kopp and Lean 2011). Distributed over the
sphere of the globe this revised estimate corresponds to a
total solar irradiance close to 340 Wm
–2
, with an uncer-
tainty range of less than 1 Wm
-2
. The GCMs typically still
use the older, somewhat higher TSI, thus showing a mul-
timodel mean of 341.2 Wm
-2
, with a standard deviation of
0.7 Wm
-2
(Table 3). Specifically, 16 out of 22 models use
a value in the small range between 341.4 and 341.6 Wm
–2
,
5 models a value of 340.4 Wm
–2
close to the SORCE
estimate, and one model a lower value of 338.9 Wm
–2
.This
signifies that the majority of the GCMs calculate slightly
too much solar irradiance at the TOA compared to the latest
estimates, on the order of 1 Wm
-2
globally.
3110 M. Wild et al.
123
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437 citations

Cites background from "The global energy balance from a su..."

  • ...(uncertainty range of 0.2 to 1.0; Wild et al., 2012)....

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  • ...Wild et al. (2012) estimated the global mean precipitation at 2.94±0.17 mm/day, while the estimate from Stephens et al. (2012) is 3.04 ± 0.35 mm/day....

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  • ...2103 Wild et al. (2012) note that the GPCP estimate may be too low due to systematic underestimations in the satellite retrievals (Stephens et al., 2012; Trenberth et al., 2009)....

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Journal Article•DOI•
Global lake responses to climate change

[...]

R. Iestyn Woolway1, R. Iestyn Woolway2, Benjamin M. Kraemer3, John D. Lenters4, John D. Lenters5, John D. Lenters6, Christopher J. Merchant7, Catherine M. O'Reilly8, Sapna Sharma9 •
European Space Agency1, Dundalk Institute of Technology2, Leibniz Association3, Michigan Technological University4, University of Wisconsin-Madison5, Wisconsin Department of Natural Resources6, University of Reading7, Illinois State University8, York University9
14 Jul 2020
TL;DR: A review of physical lake variables and their responses to climate change is presented in this paper, where the authors discuss recent and expected lake responses and look towards future research opportunities in lake monitoring and modelling.
Abstract: Climate change is one of the most severe threats to global lake ecosystems. Lake surface conditions, such as ice cover, surface temperature, evaporation and water level, respond dramatically to this threat, as observed in recent decades. In this Review, we discuss physical lake variables and their responses to climate change. Decreases in winter ice cover and increases in lake surface temperature modify lake mixing regimes and accelerate lake evaporation. Where not balanced by increased mean precipitation or inflow, higher evaporation rates will favour a decrease in lake level and surface water extent. Together with increases in extreme-precipitation events, these lake responses will impact lake ecosystems, changing water quantity and quality, food provisioning, recreational opportunities and transportation. Future research opportunities, including enhanced observation of lake variables from space (particularly for small water bodies), improved in situ lake monitoring and the development of advanced modelling techniques to predict lake processes, will improve our global understanding of lake responses to a changing climate. Climate change affects lakes worldwide and is predicted to continue to alter lake ice cover, surface temperature, evaporation rates, water levels and mixing regimes. This Review discusses recent and expected lake responses to climate change and looks towards future research opportunities in lake monitoring and modelling.

412 citations

Journal Article•DOI•
Global observations of aerosol-cloud-precipitation-climate interactions

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Daniel Rosenfeld1, Meinrat O. Andreae2, Ari Asmi3, Mian Chin4, Gerrit de Leeuw3, Gerrit de Leeuw5, David Donovan6, Ralph A. Kahn4, Stefan Kinne2, Niku Kivekäs7, Niku Kivekäs5, Markku Kulmala3, William K. M. Lau4, K. Sebastian Schmidt8, Tanja Suni3, Thomas Wagner2, Martin Wild9, Johannes Quaas10 •
Hebrew University of Jerusalem1, Max Planck Society2, University of Helsinki3, Goddard Space Flight Center4, Finnish Meteorological Institute5, Royal Netherlands Meteorological Institute6, Lund University7, University of Colorado Boulder8, ETH Zurich9, Leipzig University10
01 Dec 2014-Reviews of Geophysics
TL;DR: In this article, a roadmap is provided for quantifying the aerosol-cloud-precipitation-climate (ACPC) interactions and thereby reducing the uncertainty in anthropogenic climate forcing.
Abstract: Cloud drop condensation nuclei (CCN) and ice nuclei (IN) particles determine to a large extent cloud microstructure and, consequently, cloud albedo and the dynamic response of clouds to aerosol-induced changes to precipitation. This can modify the reflected solar radiation and the thermal radiation emitted to space. Measurements of tropospheric CCN and IN over large areas have not been possible and can be only roughly approximated from satellite-sensor-based estimates of optical properties of aerosols. Our lack of ability to measure both CCN and cloud updrafts precludes disentangling the effects of meteorology from those of aerosols and represents the largest component in our uncertainty in anthropogenic climate forcing. Ways to improve the retrieval accuracy include multiangle and multipolarimetric passive measurements of the optical signal and multispectral lidar polarimetric measurements. Indirect methods include proxies of trace gases, as retrieved by hyperspectral sensors. Perhaps the most promising emerging direction is retrieving the CCN properties by simultaneously retrieving convective cloud drop number concentrations and updraft speeds, which amounts to using clouds as natural CCN chambers. These satellite observations have to be constrained by in situ observations of aerosol-cloud-precipitation-climate (ACPC) interactions, which in turn constrain a hierarchy of model simulations of ACPC. Since the essence of a general circulation model is an accurate quantification of the energy and mass fluxes in all forms between the surface, atmosphere and outer space, a route to progress is proposed here in the form of a series of box flux closure experiments in the various climate regimes. A roadmap is provided for quantifying the ACPC interactions and thereby reducing the uncertainty in anthropogenic climate forcing.

317 citations

Journal Article•DOI•
Evapotranspiration Estimation with Remote Sensing and Various Surface Energy Balance Algorithms—A Review

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Yuei-An Liou, S.K. Kar1•
National Central University1
28 Apr 2014-Energies
TL;DR: In this paper, a review of the basic theories, observational methods, and different surface energy balance algorithms for estimating evapotranspiration (ET) from landscapes and regions with remotely sensed surface temperatures is presented.
Abstract: With the advent of new satellite technology, the radiative energy exchanges between Sun, Earth, and space may now be quantified accurately. Nevertheless, much less is known about the magnitude of the energy flows within the climate system and at the Earth’s surface, which cannot be directly measured by satellites. This review surveys the basic theories, observational methods, and different surface energy balance algorithms for estimating evapotranspiration (ET) from landscapes and regions with remotely sensed surface temperatures, and highlights uncertainties and limitations associated with those estimation methods. Although some of these algorithms were built up for specific land covers like irrigation areas only, methods developed for other disciplines like hydrology and meteorology, are also reviewed, where continuous estimates in space and in time are needed. Temporal and spatial scaling issues associated with the use of thermal remote sensing for estimating evapotranspiration are also discussed. A review of these different satellite based remote sensing approaches is presented. The main physical bases and assumptions of these algorithms are also discussed. Some results are shown for the estimation of evapotranspiration on a rice paddy of Chiayi Plain in Taiwan using remote sensing data.

270 citations

References
More filters
Journal Article•DOI•
The ERA‐40 re‐analysis

[...]

S. Uppala1, Per Kållberg1, Adrian Simmons1, U. Andrae1, V. da Costa Bechtold1, M. Fiorino2, J. K. Gibson1, J. Haseler1, A. Hernandez1, Graeme Kelly1, Xiaoming Li3, Kazutoshi Onogi4, Sami Saarinen1, N. Sokka1, Richard P. Allan5, Richard P. Allan6, Erik Andersson1, Klaus Arpe7, Magdalena Balmaseda1, Anton Beljaars1, L. van de Berg, Jean Bidlot1, Niels Bormann1, S. Caires8, Frédéric Chevallier1, A. Dethof1, M. Dragosavac1, Michael Fisher1, Manuel Fuentes1, Stefan Hagemann7, Elías Hólm1, Brian J. Hoskins6, Lars Isaksen1, Peter A. E. M. Janssen1, Roy L. Jenne9, A. P. McNally1, Jean-François Mahfouf1, Jean-Jacques Morcrette1, Nick Rayner5, Roger Saunders5, P. Simon, Andreas Sterl8, Kevin E. Trenberth9, A. Untch1, Drasko Vasiljevic1, Pedro Viterbo1, John S. Woollen10 •
European Centre for Medium-Range Weather Forecasts1, Lawrence Livermore National Laboratory2, Chinese Academy of Sciences3, Japan Meteorological Agency4, Met Office5, University of Reading6, Max Planck Society7, Royal Netherlands Meteorological Institute8, National Center for Atmospheric Research9, National Oceanic and Atmospheric Administration10
01 Oct 2005-Quarterly Journal of the Royal Meteorological Society
TL;DR: ERA-40 is a re-analysis of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions as mentioned in this paper.
Abstract: ERA-40 is a re-analysis of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions. The observing system changed considerably over this re-analysis period, with assimilable data provided by a succession of satellite-borne instruments from the 1970s onwards, supplemented by increasing numbers of observations from aircraft, ocean-buoys and other surface platforms, but with a declining number of radiosonde ascents since the late 1980s. The observations used in ERA-40 were accumulated from many sources. The first part of this paper describes the data acquisition and the principal changes in data type and coverage over the period. It also describes the data assimilation system used for ERA-40. This benefited from many of the changes introduced into operational forecasting since the mid-1990s, when the systems used for the 15-year ECMWF re-analysis (ERA-15) and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) re-analysis were implemented. Several of the improvements are discussed. General aspects of the production of the analyses are also summarized. A number of results indicative of the overall performance of the data assimilation system, and implicitly of the observing system, are presented and discussed. The comparison of background (short-range) forecasts and analyses with observations, the consistency of the global mass budget, the magnitude of differences between analysis and background fields and the accuracy of medium-range forecasts run from the ERA-40 analyses are illustrated. Several results demonstrate the marked improvement that was made to the observing system for the southern hemisphere in the 1970s, particularly towards the end of the decade. In contrast, the synoptic quality of the analysis for the northern hemisphere is sufficient to provide forecasts that remain skilful well into the medium range for all years. Two particular problems are also examined: excessive precipitation over tropical oceans and a too strong Brewer-Dobson circulation, both of which are pronounced in later years. Several other aspects of the quality of the re-analyses revealed by monitoring and validation studies are summarized. Expectations that the ‘second-generation’ ERA-40 re-analysis would provide products that are better than those from the firstgeneration ERA-15 and NCEP/NCAR re-analyses are found to have been met in most cases. © Royal Meteorological Society, 2005. The contributions of N. A. Rayner and R. W. Saunders are Crown copyright.

7,110 citations

"The global energy balance from a su..." refers methods in this paper

  • ...The satellite observations used in this study to constrain the net fluxes at the TOA stem from the CERES mission that measures filtered radiances in the solar (0.3 and 5 lm), total (0.3 and 200 lm), and window (8 and 12 lm) regions (Wielicki et al. 1996)....

    [...]

  • ...Knowledge on the energy exchange between Sun, Earth and space has recently been improved through new satellite missions such as the Clouds and the Earth’s Radiant Energy System (CERES, Wielicki et al. 1996) and the Solar Radiation and Climate Experiment (SORCE, Anderson and Cahalan 2005)....

    [...]

Journal Article•DOI•
Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave

[...]

Eli J. Mlawer, Steven J. Taubman, Patrick D. Brown, Michael J. Iacono, Shepard A. Clough 
27 Jul 1997-Journal of Geophysical Research
TL;DR: A rapid and accurate radiative transfer model (RRTM) for climate applications has been developed and the results extensively evaluated as discussed by the authors, which is performed using the correlated-k method: the k distributions are attained directly from the LBLRTM line-byline model, which connects the absorption coefficients used by RRTM to high-resolution radiance validations done with observations.
Abstract: A rapid and accurate radiative transfer model (RRTM) for climate applications has been developed and the results extensively evaluated. The current version of RRTM calculates fluxes and cooling rates for the longwave spectral region (10–3000 cm−1) for an arbitrary clear atmosphere. The molecular species treated in the model are water vapor, carbon dioxide, ozone, methane, nitrous oxide, and the common halocarbons. The radiative transfer in RRTM is performed using the correlated-k method: the k distributions are attained directly from the LBLRTM line-by-line model, which connects the absorption coefficients used by RRTM to high-resolution radiance validations done with observations. Refined methods have been developed for treating bands containing gases with overlapping absorption, for the determination of values of the Planck function appropriate for use in the correlated-k approach, and for the inclusion of minor absorbing species in a band. The flux and cooling rate results of RRTM are linked to measurement through the use of LBLRTM, which has been substantially validated with observations. Validations of RRTM using LBLRTM have been performed for the midlatitude summer, tropical, midlatitude winter, subarctic winter, and four atmospheres from the Spectral Radiance Experiment campaign. On the basis of these validations the longwave accuracy of RRTM for any atmosphere is as follows: 0.6 W m−2 (relative to LBLRTM) for net flux in each band at all altitudes, with a total (10–3000 cm−1) error of less than 1.0 W m−2 at any altitude; 0.07 K d−1 for total cooling rate error in the troposphere and lower stratosphere, and 0.75 K d−1 in the upper stratosphere and above. Other comparisons have been performed on RRTM using LBLRTM to gauge its sensitivity to changes in the abundance of specific species, including the halocarbons and carbon dioxide. The radiative forcing due to doubling the concentration of carbon dioxide is attained with an accuracy of 0.24 W m−2, an error of less than 5%. The speed of execution of RRTM compares favorably with that of other rapid radiation models, indicating that the model is suitable for use in general circulation models.

6,861 citations

Additional excerpts

  • ...These reanalyses include the Rapid Radiation Transfer Model (RRTM, Mlawer et al. 1997), which was shown to substantially reduce biases against surface observations when used in a climate model (Wild and Roeckner 2006)....

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Journal Article•DOI•
Aerosols, climate, and the hydrological cycle

[...]

Veerabhadran Ramanathan1, Paul J. Crutzen2, Paul J. Crutzen1, Jeffrey T. Kiehl3, Daniel Rosenfeld4 •
University of California, San Diego1, Max Planck Society2, National Center for Atmospheric Research3, Hebrew University of Jerusalem4
07 Dec 2001-Science
TL;DR: Human activities are releasing tiny particles (aerosols) into the atmosphere that enhance scattering and absorption of solar radiation, which can lead to a weaker hydrological cycle, which connects directly to availability and quality of fresh water, a major environmental issue of the 21st century.
Abstract: Human activities are releasing tiny particles (aerosols) into the atmosphere. These human-made aerosols enhance scattering and absorption of solar radiation. They also produce brighter clouds that are less efficient at releasing precipitation. These in turn lead to large reductions in the amount of solar irradiance reaching Earth's surface, a corresponding increase in solar heating of the atmosphere, changes in the atmospheric temperature structure, suppression of rainfall, and less efficient removal of pollutants. These aerosol effects can lead to a weaker hydrological cycle, which connects directly to availability and quality of fresh water, a major environmental issue of the 21st century.

3,469 citations

Journal Article•DOI•
Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment

[...]

Bruce A. Wielicki1, Bruce R. Barkstrom1, Edwin F. Harrison1, Robert Benjamin Lee1, G. Louis Smith1, John E. Cooper1 •
Langley Research Center1
01 May 1996-Bulletin of the American Meteorological Society
TL;DR: The CERES broadband scanning radiometers are an improved version of the Earth Radiation Budget Experiment (ERBE) radiometers as mentioned in this paper, which is an investigation to examine the role of cloud/radiation feedback in the Earth's climate system.
Abstract: Clouds and the Earth's Radiant Energy System (CERES) is an investigation to examine the role of cloud/radiation feedback in the Earth's climate system. The CERES broadband scanning radiometers are an improved version of the Earth Radiation Budget Experiment (ERBE) radiometers. The CERES instruments will fly on several National Aeronautics and Space Administration Earth Observing System (EOS) satellites starting in 1998 and extending over at least 15 years. The CERES science investigations will provide data to extend the ERBE climate record of top-of-atmosphere shortwave (SW) and longwave (LW) radiative fluxes CERES will also combine simultaneous cloud property data derived using EOS narrowband imagers to provide a consistent set of cloud/radiation data, including SW and LW radiative fluxes at the surface and at several selected levels within the atmosphere. CERES data are expected to provide top-of-atmosphere radiative fluxes with a factor of 2 to 3 less error than the ERBE data Estimates of radiative fluxes at the surface and especially within the atmosphere will be a much greater challenge but should also show significant improvements over current capabilities.

1,804 citations

"The global energy balance from a su..." refers methods in this paper

  • ...The satellite observations used in this study to constrain the net fluxes at the TOA stem from the CERES mission that measures filtered radiances in the solar (0.3 and 5 lm), total (0.3 and 200 lm), and window (8 and 12 lm) regions (Wielicki et al. 1996)....

    [...]

  • ...Knowledge on the energy exchange between Sun, Earth and space has recently been improved through new satellite missions such as the Clouds and the Earth’s Radiant Energy System (CERES, Wielicki et al. 1996) and the Solar Radiation and Climate Experiment (SORCE, Anderson and Cahalan 2005)....

    [...]

Journal Article•DOI•
Cloud-radiative forcing and climate: results from the Earth radiation budget experiment.

[...]

Veerabhadran Ramanathan1, R. D. Cess2, Edwin F. Harrison3, Patrick Minnis3, Bruce R. Barkstrom3, E. Ahmad1, Dennis L. Hartmann4 •
University of Chicago1, Stony Brook University2, Langley Research Center3, University of Washington4
06 Jan 1989-Science
TL;DR: The size of the observed net cloud forcing is about four times as large as the expected value of radiative forcing from a doubling of CO2, and small changes in the cloud-radiative forcing fields can play a significant role as a climate feedback mechanism.
Abstract: The spaceborne Earth Radiation Budget Experiment was begun in 1984 to obtain quantitative estimates of the global distributions of cloud-radiative forcing The magnitude of the observed net cloud forcing is about four times greater than the expected value of radiative forcing from a doubling of CO2; the shortwave and longwave components of cloud forcing are about 10 times as large as those for a CO2 doubling Small changes in the cloud-radiative forcing fields can therefore play a significant role as a climate-feedback mechanism

1,631 citations

"The global energy balance from a su..." refers background in this paper

  • ...…Bussestrasse 24, 27570 Bremerhaven, Germany in numerous studies published over the past decades (e.g., Hartmann and Short 1980; Hartmann et al. 1986; Ramanathan et al. 1989; Gutowski et al. 1991; Ohmura and Gilgen 1993; Pinker et al. 1995; Li et al. 1997; Gleckler and Weare 1997; Kiehl and…...

    [...]

Related Papers (5)
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01 Mar 2009-Bulletin of the American Meteorological Society
Kevin E. Trenberth, John T. Fasullo, Jeffrey T. Kiehl
The ERA-Interim reanalysis: configuration and performance of the data assimilation system

[...]

01 Apr 2011-Quarterly Journal of the Royal Meteorological Society
Dick Dee, S. Uppala, Adrian Simmons, Paul Berrisford, Paul Poli, Shinya Kobayashi, Ulf Andrae, Magdalena Balmaseda, Gianpaolo Balsamo, Peter Bauer, Peter Bechtold, Anton Beljaars, L. van de Berg, Jean Bidlot, Niels Bormann, C. Delsol, Rossana Dragani, Manuel Fuentes, Alan J. Geer, Leopold Haimberger, Sean Healy, Hans Hersbach, Elías Hólm, Lars Isaksen, P. Kallberg, Martin Köhler, Marco Matricardi, A. P. McNally, B. M. Monge-Sanz, Jean-Jacques Morcrette, B.-K. Park, Carole Peubey, P. de Rosnay, Christina Tavolato, Jean-Noël Thépaut, Frederic Vitart 
Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment

[...]

01 May 1996-Bulletin of the American Meteorological Society
Bruce A. Wielicki, Bruce R. Barkstrom, Edwin F. Harrison, Robert Benjamin Lee, G. Louis Smith, John E. Cooper 
Baseline surface radiation network (BSRN/WCRP) New precision radiometry for climate research

[...]

01 Oct 1998-Bulletin of the American Meteorological Society
Atsumu Ohmura, Ellsworth G. Dutton, Bruce W. Forgan, Claus Fröhlich, Hans Gilgen, Herman Hegner, Alain Heimo, Gert König-Langlo, Bruce McArthur, Guido Müller, Rolf Philipona, Rachel T. Pinker, Charlie H. Whitlock, Klaus Dehne, Martin Wild 
Earth's annual global mean energy budget

[...]

01 Feb 1997-Bulletin of the American Meteorological Society
Jeffrey T. Kiehl, Kevin E. Trenberth
Frequently Asked Questions (6)
Q1. What have the authors contributed in "The global energy balance from a surface perspective" ?

The authors combine these observations with the latest modeling efforts performed for the 5th IPCC assessment report to infer best estimates for the global mean surface radiative components. The findings of this study are compiled into a new global energy balance diagram, which may be able to reconcile currently disputed inconsistencies between energy and water cycle estimates. This also suggests that, globally, the simulated surface sensible and latent heat fluxes, around 20 and 85 Wm on average, state realistic values. 

The semiempirical formulations of the water vapor continuum are considered as a major source of uncertainty in the thermal flux calculations (Wild et al. 2001; Iacono et al. 2000). 

The accuracy of downward thermal radiation measurements, carried out with pyrgeometers, is near 3–4 Wm-2 according to Philipona et al. (2001) and Marty et al. (2003), thereby meeting BSRN standards established by Ohmura et al. (1998). 

With 24 Wm-2 reflected out of the total of 185 Wm-2 of downward solar radiation, this leaves an amount of 161 Wm-2 absorbed at the Earth’s surface (Fig. 1). 

Due to the necessity to track the sun with the pyrheliometer and the shading disk, data gaps in the direct and diffuse records are typically more frequent than with the pyranometer measurements, which explains the slightly lower number of stations available for climatologies based on combined direct and diffuse measurements. 

The uncertainty range for the atmospheric solar absorption given in Fig. 1 is larger than for the other components, since, determined as a residual, the uncertainty ranges of the surface (12 Wm-2) and TOA (5 Wm-2) solar absorption are additive.