Drafting Authors: Neil Adger, Pramod Aggarwal, Shardul Agrawala, Joseph Alcamo, Abdelkader Allali, Oleg Anisimov, Nigel Arnell, Michel Boko, Osvaldo Canziani, Timothy Carter, Gino Casassa, Ulisses Confalonieri, Rex Victor Cruz, Edmundo de Alba Alcaraz, William Easterling, Christopher Field, Andreas Fischlin, Blair Fitzharris, Carlos Gay García, Clair Hanson, Hideo Harasawa, Kevin Hennessy, Saleemul Huq, Roger Jones, Lucka Kajfež Bogataj, David Karoly, Richard Klein, Zbigniew Kundzewicz, Murari Lal, Rodel Lasco, Geoff Love, Xianfu Lu, Graciela Magrín, Luis José Mata, Roger McLean, Bettina Menne, Guy Midgley, Nobuo Mimura, Monirul Qader Mirza, José Moreno, Linda Mortsch, Isabelle Niang-Diop, Robert Nicholls, Béla Nováky, Leonard Nurse, Anthony Nyong, Michael Oppenheimer, Jean Palutikof, Martin Parry, Anand Patwardhan, Patricia Romero Lankao, Cynthia Rosenzweig, Stephen Schneider, Serguei Semenov, Joel Smith, John Stone, Jean-Pascal van Ypersele, David Vaughan, Coleen Vogel, Thomas Wilbanks, Poh Poh Wong, Shaohong Wu, Gary Yohe

Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change

Evidence gleaned from the instrumental record of climate data identifies a robust, recurring pattern of ocean–atmosphere climate variability centered over the midlatitude North Pacific basin. Over the past century, the amplitude of this climate pattern has varied irregularly at interannual-to-interdecadal timescales. There is evidence of reversals in the prevailing polarity of the oscillation occurring around 1925, 1947, and 1977; the last two reversals correspond to dramatic shifts in salmon production regimes in the North Pacific Ocean. This climate pattern also affects coastal sea and continental surface air temperatures, as well as streamflow in major west coast river systems, from Alaska to California.

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A Pacific interdecadal climate oscillation with impacts on salmon production

The NCEP Climate Forecast System Reanalysis (CFSR) was completed for the 31-yr period from 1979 to 2009, in January 2010. The CFSR was designed and executed as a global, high-resolution coupled atmosphere–ocean–land surface–sea ice system to provide the best estimate of the state of these coupled domains over this period. The current CFSR will be extended as an operational, real-time product into the future. New features of the CFSR include 1) coupling of the atmosphere and ocean during the generation of the 6-h guess field, 2) an interactive sea ice model, and 3) assimilation of satellite radiances by the Gridpoint Statistical Interpolation (GSI) scheme over the entire period. The CFSR global atmosphere resolution is ~38 km (T382) with 64 levels extending from the surface to 0.26 hPa. The global ocean's latitudinal spacing is 0.25° at the equator, extending to a global 0.5° beyond the tropics, with 40 levels to a depth of 4737 m. The global land surface model has four soil levels and the global sea ice m...

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The NCEP Climate Forecast System Reanalysis

One of the major concerns with a potential change in climate is that an increase in extreme events will occur. Results of observational studies suggest that in many areas that have been analyzed, changes in total precipitation are amplified at the tails, and changes in some temperature extremes have been observed. Model output has been analyzed that shows changes in extreme events for future climates, such as increases in extreme high temperatures, decreases in extreme low temperatures, and increases in intense precipitation events. In addition, the societal infrastructure is becoming more sensitive to weather and climate extremes, which would be exacerbated by climate change. In wild plants and animals, climate-induced extinctions, distributional and phenological changes, and species' range shifts are being documented at an increasing rate. Several apparently gradual biological changes are linked to responses to extreme weather and climate events.

https://www7.nau.edu/mpcer/direnet/publications/publications_e/files/Easterling_et_al_2000.pdf

Climate Extremes: Observations, Modeling, and Impacts

Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

Since 1951, the biomass of macrozooplankton in waters off southern California has decreased by 80 percent. During the same period, the surface layer warmed—by more than 1.5°C in some places—and the temperature difference across the thermocline increased. Increased stratification resulted in less lifting of the thermocline by wind-driven upwelling. A shallower source of upwelled waters provided less inorganic nutrient for new biological production and hence supported a smaller zooplankton population. Continued warming could lead to further decline of zooplankton.

Climatic Warming and the Decline of Zooplankton in the California Current

The 2004-2008 mean and annual cycle of temperature, salinity, and steric height in the global ocean from the Argo Program

Author Posting. © Oceanography Society, 2009. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 22 no. 2 (2009): 34-43.

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The Argo Program : observing the global ocean with profiling floats

[1] Satellite altimetric height was combined with approximately 1,000,000 in situ temperature profiles to produce global estimates of upper ocean heat content, temperature, and thermosteric sea level variability on interannual timescales. Maps of these quantities from mid-1993 through mid-2003 were calculated using the technique developed by Willis et al. [2003]. The time series of globally averaged heat content contains a small amount of interannual variability and implies an oceanic warming rate of 0.86 ± 0.12 watts per square meter of ocean (0.29 ± 0.04 pW) from 1993 to 2003 for the upper 750 m of the water column. As a result of the warming, thermosteric sea level rose at a rate of 1.6 ± 0.3 mm/yr over the same time period. Maps of yearly heat content anomaly show patterns of warming commensurate with ENSO variability in the tropics, but also show that a large part of the trend in global, oceanic heat content is caused by regional warming at midlatitudes in the Southern Hemisphere. In addition to quantifying interannual variability on a global scale, this work illustrates the importance of maintaining continuously updated monitoring systems that provide global coverage of the world's oceans. Ongoing projects, such as the Jason/TOPEX series of satellite altimeters and the Argo float program, provide a critical foundation for characterizing variability on regional, basin, and global scales and quantifying the oceans' role as part of the climate system.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003JC002260

Interannual variability in upper ocean heat content, temperature, and thermosteric expansion on global scales

Transatlantic hydrographic sections were obtained in mid-1981 along latitudes 24.5° and 36.25°N. The tracks nearly duplicated sections made 23 years earlier as part of the International Geophysical Year. A total of 215 stations were occupied: data from a conductivity-temperature-depth (CTD) probe and water samples for analyses of oxygen, nutrient, and other tracer concentrations were collected from the ocean surface to near bottom. The 1981 sections are described and displayed, and the circulation is compared to that of the earlier survey. Large-scale meridional velocity and basin-integrated transport are compared in the 1981 and IGY sections, using a hierarchy of geostrophic models. In the simplest model, a reference level is based on the gross thermohaline flow and consideration of water mass characteristics. The only transport constraint is that the geostrophic plus Ekman flows sum to zero. Subsequent models impose mass conservation in a set of layers and then conservation of potential vorticity in a single layer. Distributions of salinity and potential vorticity on density surfaces are examined in order to identify layers in which an advective balance of tracer distribution is plausible and where gradients are strong enough to be of practical use. It was found that the 1981 and IGY sections have similar features in their large-scale velocity fields and similar zonally averaged meridional transport. In each case, net northward transports of approximately 17 Sv of surface and intermediate water (above σ 2 = 36.82) were balanced by equal southward flow in the deep water. A significant shift toward greater depth occurred in the depth distribution of the deep southward flow in the 1981 sections. The wind-driven subtropical gyre is superimposed on this thermohaline overturning, and transport calculations in the gyre interior show the Sverdrup relation to be of questionable direct applicability. Ocean heat transport in 1981 was found to be about 1.2 × 10 15 W across 24°N and 0.8 × 10 15 W across 36°N. These values are indistinguishable from those obtained from the IGY data and from computations of air-sea heat exchange. The steadiness of the heat transport is attributed to the invariance of the zonally averaged meridional circulation.

Dean Roemmich

Papers

Climatic Warming and the Decline of Zooplankton in the California Current

The 2004-2008 mean and annual cycle of temperature, salinity, and steric height in the global ocean from the Argo Program

The Argo Program : observing the global ocean with profiling floats

Interannual variability in upper ocean heat content, temperature, and thermosteric expansion on global scales

Two transatlantic sections: meridional circulation and heat flux in the subtropical North Atlantic Ocean