Showing papers in "Bulletin of the American Meteorological Society in 2005"
TL;DR: In this article, the authors examined manual and telemetered measurements of spring snowpack, corroborated by a physically based hydrologic model, for climate-driven fluctuations and trends during the period of 1916-2002.
Abstract: In western North America, snow provides crucial storage of winter precipitation, effectively transferring water from the relatively wet winter season to the typically dry summers. Manual and telemetered measurements of spring snowpack, corroborated by a physically based hydrologic model, are examined here for climate-driven fluctuations and trends during the period of 1916–2002. Much of the mountain West has experienced declines in spring snowpack, especially since midcentury, despite increases in winter precipitation in many places. Analysis and modeling show that climatic trends are the dominant factor, not changes in land use, forest canopy, or other factors. The largest decreases have occurred where winter temperatures are mild, especially in the Cascade Mountains and northern California. In most mountain ranges, relative declines grow from minimal at ridgetop to substantial at snow line. Taken together, these results emphasize that the West's snow resources are already declining as earth's climate warms.
1,435 citations
TL;DR: In this paper, the authors examined the mathematical basis and accuracy of the relationship between the dewpoint and relative humidity, and proposed a simple rule of thumb that can be very useful for approximating the conversion for moist air, which does not appear to be widely known by the meteorological community.
Abstract: The relative humidity (RH) and the dewpoint temperature (td) are two widely used indicators of the amount of moisture in air. The exact conversion from RH to td, as well as highly accurate approximations, are too complex to be done easily without the help of a calculator or computer. However, there is a very simple rule of thumb that can be very useful for approximating the conversion for moist air (RH > 50%), which does not appear to be widely known by the meteorological community: td decreases by about 1°C for every 5% decrease in RH (starting at td= t, the dry bulb temperature, when RH = 100%). This article examines the mathematical basis and accuracy of this and other relationships between the dewpoint and relative humidity. Several useful applications of the simple conversion are presented, in particular the computation of the cumulus cloud-base level (or lifting condensation level) as zLCL >> (20 + t/5)(100 – RH), where zLCL is in meters when t is in degrees Celcius and RH in percent. Finally, a his...
885 citations
TL;DR: The authors reviewed recent research on tropical cyclones and climate change from the perspective of event risk, vulnerability, and outcome risk, concluding that with no trend identified in various metrics of hurricane damage over the twentieth century, it is exceedingly unlikely that scientists will identify large changes in historical storm behavior that have significant societal implications, though scientists may identify discernible changes in storm behavior.
Abstract: This paper reviews recent research on tropical cyclones and climate change from the perspective of event risk—the physical behavior of storms; vulnerability—the characteristics of a system that create the potential for impacts, but are independent of event risk; and also outcome risk—the integration of considerations of vulnerability with event risk to characterize an event that causes losses. The paper concludes that with no trend identified in various metrics of hurricane damage over the twentieth century, it is exceedingly unlikely that scientists will identify large changes in historical storm behavior that have significant societal implications, though scientists may identify discernible changes in storm behavior. Looking to the future, until scientists conclude a) that there will be changes to storms that are significantly larger than observed in the past, b) that such changes are correlated to measures of societal impact, and c) that the effects of such changes are significant in the context of ine...
531 citations
TL;DR: The Advanced Baseline Imager (ABI) as discussed by the authors was designed to be one of the instruments on a future Geo-stationary Operational Environmental Satellite (GOES) series, which will introduce a new era for U.S. geostationary environmental remote sensing.
Abstract: The Advanced Baseline Imager (ABI), designated to be one of the instruments on a future Geo-stationary Operational Environmental Satellite (GOES) series, will introduce a new era for U.S. geostationary environmental remote sensing. ABI is slated to be launched on GOES-R in 2012 and will be used for a wide range of weather, oceanographic, climate, and environmental applications. ABI will have more spectral bands (16), faster imaging (enabling more geographical areas to be scanned), and higher spatial resolution (2 km in the infrared and 1–0.5 km in the visible) than the current GOES Imager. The purposes of the selected spectral bands are summarized in this paper. There will also be improved performance with regard to radiometrics and image navigation/registration. ABI will improve all current GOES Imager products and introduce a host of new products. New capabilities will include detecting upper-level SO2 plumes, monitoring plant health on a diurnal time scale, inferring cloud-top phase and partic...
492 citations
TL;DR: The problem of creating truly convincing numerical simulations of the Earth's climate will remain a challenge for the next generation of climate scientists, and one of the key issues will need to address is the widening gap between simulation and understanding.
Abstract: The problem of creating truly convincing numerical simulations of our Earth's climate will remain a challenge for the next generation of climate scientists. Hopefully, the ever increasing power of computers will make this task somewhat less frustrating than it is at present. But, increasing computational power also raises issues as to how we would like to see climate modeling and the study of climate dynamics evolve in the twenty-first century. One of the key issues we will need to address is the widening gap between simulation and understanding.
460 citations
TL;DR: A survey of the state of the art on homogeneous and heterogeneous nucleation can be found in this paper, where the authors survey the state-of-the-art on the underlying mechanisms of nucleation in the troposphere.
Abstract: Ice in the troposphere affects a variety of processes, including the formation of precipitation, and cloud lifetime, albedo, dynamics, and electrification. A lack of understanding of the ways in which ice is created and multiplied hampers progress in understanding all of these processes. We survey the state of knowledge, starting with homogeneous nucleation, where current formulations for freezing from both pure water and solutions have considerable predictive power. However, debate still exists on the underlying mechanisms of nucleation. Using the concepts and framework that homogeneous nucleation provides, heterogeneous nucleation, where neither a commonly agreed upon theory nor even standard measurement technique exists, is considered. Investigators have established the ice-nucleating characteristics of broad classes of substances, such as mineral dust and soot, which are important ice nuclei in t he atmosphere, but a coherent theory of why these substances act as they do has yet to emerge. All ice in ...
376 citations
TL;DR: In this paper, the authors presented an overview of polarimetric algorithms for rainfall estimation and hydrometeor classification and their performance during the Joint Polarization Experiment (JPOLE).
Abstract: As part of the evolution and future enhancement of the Next Generation Weather Radars (NEXRAD), the National Severe Storms Laboratory recently upgraded the KOUN Weather Surveillance Radar-1988 Doppler (WSR-88D) to include a polarimetric capability. The proof of concept was tested in central Oklahoma during a 1-yr demonstration project referred to as the Joint Polarization Experiment (JPOLE). This paper presents an overview of polarimetric algorithms for rainfall estimation and hydrometeor classification and their performance during JPOLE. The quality of rainfall measurements is validated on a large dataset from the Oklahoma Mesonet and Agricultural Research Service Micronet rain gauge networks. The comparison demonstrates that polarimetric rainfall estimates are often dramatically superior to those provided by conventional rainfall algorithms. Using a synthetic R(Z, KDP, ZDR) polarimetric rainfall relation, rms errors are reduced by a factor of 1.7 for point measurements and 3.7 for areal estimates [when ...
360 citations
TL;DR: In this paper, a prototype tool for improving fine particulate matter (PM2.5) air quality forecasts using satellite aerosol observations was demonstrated, and daily forecast products were generated from a near-real-time fusion of multiple input data products, including aerosol optical depth (AOD) from the MODIS)/Earth Observing System (EOS) instrument on the NASA Terra satellite.
Abstract: Accurate air quality forecasts can allow for mitigation of the health risks associated with high levels of air pollution. During September 2003, a team of NASA, NOAA, and EPA researchers demonstrated a prototype tool for improving fine particulate matter (PM2.5) air quality forecasts using satellite aerosol observations. Daily forecast products were generated from a near-real-time fusion of multiple input data products, including aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS)/Earth Observing System (EOS) instrument on the NASA Terra satellite, PM2.5 concentration from over 300 state/local/national surface monitoring stations, meteorological fields from the NOAA/NCEP Eta Model, and fire locations from the NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) Geostationary Operational Environmental Satellite (GOES) Wildfire Automated Biomass Burning Algorithm (WF_ABBA) product. The products were disseminated via a Web interface to a small g...
331 citations
TL;DR: The Coupled Model Intercomparison Project (CMIP) as mentioned in this paper involves study and intercomparisons of multimodel simulations of present and future climate, typically, components representing atmosphere, ocean, sea ice, and land surface.
Abstract: The Coupled Model Intercomparison Project (CMIP) involves study and intercomparison of multimodel simulations of present and future climate. The simulations of the future use idealized forcing in which CO, increase is compounded 1% yr(-1) until it doubles (near year 70) with global coupled models that contain, typically, components representing atmosphere, ocean, sea ice, and land surface. Results from CMIP diagnostic sub-projects were presented at the Second CMIP Workshop held at the Max Planck Institute for Meteorology in Hamburg, Germany, in September 2003. Significant progress in diagnosing and understanding results from global coupled models has been made since the time of the First CMIP Workshop in Melbourne, Australia, in 1998. For example, the issue of flux adjustment is slowly fading as more and more models obtain stable multicentury surface climates without them. El Nino variability, usually about half the observed amplitude in the previous generation of coupled models, is now more accurately simulated in the present generation of global coupled models, though there are still biases in simulating the patterns of maximum variability. Typical resolutions of atmospheric component models contained in coupled models are now usually around 2.5degrees latitude-longitude, with the ocean components often having about twice the atmospheric model resolution, with even higher resolution in the equatorial Tropics. Some new-generation coupled models have atmospheric resolutions of around 1.5degrees latitude - longitude. Modeling groups now routinely run the CMIP control and 1% CO2 simulations in addition to twentieth- and twenty-first-century climate simulations with a variety of forcings e.g., volcanoes, solar variability, anthropogenic sulfate aerosols, ozone, and greenhouse gases, with the anthropogenic forcings for future climate as well. However, persistent systematic errors noted in previous generations of global coupled models are still present in the current generation (e.g., overextensive equatorial Pacific cold tongue, double ITCZ). This points to the next challenge for the global coupled climate modeling community. Planning and commencement of the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) has prompted rapid coupled model development, which is leading to an expanded CMIP-like activity to collect and analyze results for the control, 1% CO2, and twentieth-, twenty-first, and twenty-second-century simulations performed for the AR4. The international climate community is encouraged to become involved in this analysis effort.
325 citations
TL;DR: In this article, a group of researchers initiated an interdisciplinary study of climate variability, scientific uncertainty, and hydrometeorological information for flood-risk decision making, focused on Colorado's Rocky Mountain Front Range urban corridor.
Abstract: The magnitude of flood damage in the United States, combined with the uncertainty in current estimates of flood risk, suggest that society could benefit from improved scientific information about flood risk. To help address this perceived need, a group of researchers initiated an interdisciplinary study of climate variability, scientific uncertainty, and hydrometeorological information for flood-risk decision making, focused on Colorado's Rocky Mountain Front Range urban corridor. We began by investigating scientific research directions that were likely to benefit flood-risk estimation and management, through consultation with climatologists, hydrologists, engineers, and planners. In doing so, we identified several challenges involved in generating new scientific information to aid flood management in the presence of significant scientific and societal uncertainty. This essay presents lessons learned from this study, along with our observations on the complex interactions among scientific information, unc...
297 citations
TL;DR: In this article, the authors present the results of a workshop at the University of Maryland Inn and Conference Center, College Park, Maryland, 12-14 November 2002, where 75 scientists participated including researchers who develop and analyze long-term datasets from satellites, experts in the field of satellite instrument calibration, and phy...
Abstract: Measuring the small changes associated with long-term global climate change from space is a daunting task. The satellite instruments must be capable of observing atmospheric and surface temperature trends as small as 0.1°C decade−1, ozone changes as little as 1% decade−1, and variations in the sun's output as tiny as 0.1% decade−1. To address these problems and recommend directions for improvements in satellite instrument calibration, the National Institute of Standards and Technology (NIST), National Polar-orbiting Operational Environmental Satellite System–Integrated Program Office (NPOESS-IPO), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) organized a workshop at the University of Maryland Inn and Conference Center, College Park, Maryland, 12–14 November 2002. Some 75 scientists participated including researchers who develop and analyze long-term datasets from satellites, experts in the field of satellite instrument calibration, and phy...
TL;DR: The Regional Climate Model Intercomparison Project (RMIP) for Asia has been established to evaluate and improve regional climate model (RCM) simulations of the monsoon climate as mentioned in this paper.
Abstract: Improving the simulation of regional climate change is one of the high-priority areas of climate study because regional information is needed for climate change impact assessments. Such information is especially important for the region covered by the East Asian monsoon where there is high variability in both space and time. To this end, the Regional Climate Model Intercomparison Project (RMIP) for Asia has been established to evaluate and improve regional climate model (RCM) simulations of the monsoon climate. RMIP operates under joint support of the Asia–Pacific Network for Global Change Research (APN), the Global Change System for Analysis, Research and Training (START), the Chinese Academy of Sciences, and several projects of participating nations. The project currently involves 10 research groups from Australia, China, Japan, South Korea, and the United States, as well as scientists from India, Italy, Mongolia, North Korea, and Russia. RMIP has three simulation phases: March 1997–August 1998, which c...
TL;DR: The Atmospheric Dynamics Mission (ADM) as discussed by the authors demonstrated measurements of vertical wind profiles from space using a high-performance Doppler wind lidar based on direct-detection interferometric techniques.
Abstract: The prime aim of the Atmospheric Dynamics Mission is to demonstrate measurements of vertical wind profiles from space. Extensive studies conducted by the European Space Agency over the past 15 years have culminated in the selection of a high-performance Doppler wind lidar based on direct-detection interferometric techniques. Such a system, with a pulsed laser operating at 355-nm wavelength, would utilize both Rayleigh scattering from molecules and Mie scattering from thin cloud and aerosol particles; measurement of the residual Doppler shift from successive levels in the atmosphere provides the vertical wind profiles. The lidar would be accommodated on a satellite flying in a sun-synchronous orbit, at an altitude of ~400 km, providing near-global coverage; target date for launch is in 2007. Processing of the backscatter signals will provide about 3000 globally distributed wind profiles per day, above thick clouds or down to the surface in clear air, at typically 200-km separation along the satellite track...
TL;DR: Open cells are associated with a reduction in cloud cover, which provides direct evidence of a connection between cloudiness and precipitation as mentioned in this paper, which is the linchpin of hypotheses that posit that changes in the atmospheric aerosol and precipitation are correlated.
Abstract: Data from recent field studies in the northeast and southeast Pacific are used to investigate pockets of open cells (POCs) that are embedded in otherwise uniform stratocumulus. The cellular structure within a POC resembles broader regions of open cellular convection typically found further offshore. In both regions, cells are composed of precipitating cell walls and cell interiors with depleted cloud water and even clearing. POCs are long lived and embedded in broader regions of stratocumulus where average droplet sizes are relatively large. In contrast, stratiform, or unbroken, cloud formations tend to be accompanied by less, or no, drizzle, suggesting that precipitation is necessary for the sustenance of the open cellular structure. Because, by definition, open cells are associated with a reduction in cloud cover these observations provide direct evidence of a connection between cloudiness and precipitation—a linchpin of hypotheses that posit a connection between changes in the atmospheric aerosol and c...
TL;DR: The Geostationary Earth Radiation Budget (GERB) experiment as discussed by the authors was designed to make the first measurements of the Earth's radiation budget from geostatary orbit using a spin-stabilized spacecraft platform.
Abstract: This paper reports on a new satellite sensor, the Geostationary Earth Radiation Budget (GERB) experiment. GERB is designed to make the first measurements of the Earth's radiation budget from geostationary orbit. Measurements at high absolute accuracy of the reflected sunlight from the Earth, and the thermal radiation emitted by the Earth are made every 15 min, with a spatial resolution at the subsatellite point of 44.6 km (north–south) by 39.3 km (east–west). With knowledge of the incoming solar constant, this gives the primary forcing and response components of the top-of-atmosphere radiation. The first GERB instrument is an instrument of opportunity on Meteosat-8, a new spin-stabilized spacecraft platform also carrying the Spinning Enhanced Visible and Infrared (SEVIRI) sensor, which is currently positioned over the equator at 3.5°W. This overview of the project includes a description of the instrument design and its preflight and in-flight calibration. An evaluation of the instrument performan...
TL;DR: In this paper, a mathematical model of heat flow from the upwind side of a head-sized cylinder moving at walking speed into the wind was used to generate the new wind chill charts.
Abstract: The formula used in the U.S. and Canada to express the combined effect of wind and low temperature on how cold it feels was changed in November 2001. Many had felt that the old formula for equivalent temperature, derived in the 1960s from Siple and Passel's flawed but quite useful Wind Chill Index, unnecessarily exaggerated the severity of the weather. The new formula is based on a mathematical model of heat flow from the upwind side of a head-sized cylinder moving at walking speed into the wind. The paper details the assumptions that were made in generating the new wind chill charts. It also points out weaknesses in the concept of wind chill equivalent temperature, including its steady-state character and a seemingly paradoxical effect of the internal thermal resistance of the cylinder on comfort and equivalent temperature. Some improvements and alternatives are suggested.
TL;DR: In this article, the authors proposed a method for extracting atmospheric motion vectors (AMVs) from satellite data and applied it to weather analysis and forecasting. But, the AMV processing methods are continuously being updated and advanced through the exploitation of new sensor technologies and innovative new approaches.
Abstract: The evolving constellation of environmental/meteorological satellites and their associated sensor technology is rapidly advancing. This is providing opportunities for creatively improving satellite-derived products used in weather analysis and forecasting. For example, the retrieval methods for deriving atmospheric motion vectors (AMVs) from satellites have been expanding and evolving since the early 1970s. Contemporary AMV processing methods are continuously being updated and advanced through the exploitation of new sensor technologies and innovative new approaches. It is incumbent upon the research community working in AMV extraction techniques to ensure that the quality of the current operational products meets or exceeds the needs of the user community. In particular, the advances in data assimilation and numerical weather prediction in recent years have placed an increasing demand on data quality. To keep pace with these demands, innovative research toward improving methods of deriving winds from sat...
TL;DR: The Advanced Microwave Scanning Radiometer on the NASA Earth Observing System (EOS) Aqua satellite (AMSR-E) is providing the first highly accurate and glob... as discussed by the authors.
Abstract: Obtaining global sea surface temperature (SST) fields for the ocean boundary condition in numerical weather prediction (NWP) models and for climate research has long been problematic. Historically, such fields have been constructed by a blending of in situ observations from ships and buoys and satellite infrared observations from the Advanced Very High Resolution Radiometer (AVHRR) that has been operational on NOAA satellites since November 1981. The resolution of these global SST fields is limited by the sparse coverage of in situ observations in many areas of the World Ocean and cloud contamination of AVHRR observations, which can exceed 75% over the subpolar oceans. As clouds and aerosols are essentially transparent to microwave radiation, satellite microwave observations can greatly improve the sampling and resolution of global SST fields. The Advanced Microwave Scanning Radiometer on the NASA Earth Observing System (EOS) Aqua satellite (AMSR-E) is providing the first highly accurate and glob...
TL;DR: A case study from the Texas Air Quality Study 2000 field campaign illustrates the complex interaction of meteorological and chemical processes that produced a high-pollution event in the Houston area on 30 August 2000 as mentioned in this paper.
Abstract: A case study from the Texas Air Quality Study 2000 field campaign illustrates the complex interaction of meteorological and chemical processes that produced a high-pollution event in the Houston area on 30 August 2000. High 1-h ozone concentrations of nearly 200 ppb were measured near the surface, and vertical profile data from an airborne differential-absorption lidar (DIAL) system showed that these high-ozone concentrations penetrated to heights approaching 2 km into the atmospheric boundary layer. This deep layer of pollution was transported over the surrounding countryside at night, where it then mixed out the next day to become part of the rural background levels. These background levels thus increased during the course of the multiday pollution episode. The case study illustrates many processes that numerical forecast models must faithfully represent to produce accurate quantitative predictions of peak pollutant concentrations in coastal locations such as Houston. Such accurate predictions ...
Goddard Space Flight Center1, University of Maryland, Baltimore2, University of Colorado Boulder3, Los Alamos National Laboratory4, National Oceanic and Atmospheric Administration5, Raytheon6, German Aerospace Center7, California Institute of Technology8, Pacific Northwest National Laboratory9, Environment Canada10, Florida State University11, University of California, Los Angeles12, Max Planck Society13, University of California, Santa Barbara14, Colorado State University15, Russian Academy of Sciences16, Kurchatov Institute17
TL;DR: The International Intercomparison of 3D Radiation Codes (I3RC) as mentioned in this paper has been proposed to compare the performance of different 3D radiative transfer codes used in a variety of current scientific work in the atmospheric sciences.
Abstract: The interaction of clouds with solar and terrestrial radiation is one of the most important topics of climate research. In recent years it has been recognized that only a full three-dimensional (3D) treatment of this interaction can provide answers to many climate and remote sensing problems, leading to the worldwide development of numerous 3D radiative transfer (RT) codes. The international Intercomparison of 3D Radiation Codes (I3RC), described in this paper, sprung from the natural need to compare the performance of these 3D RT codes used in a variety of current scientific work in the atmospheric sciences. I3RC supports intercomparison and development of both exact and approximate 3D methods in its effort to 1) understand and document the errors/limits of 3D algorithms and their sources; 2) provide “baseline” cases for future code development for 3D radiation; 3) promote sharing and production of 3D radiative tools; 4) derive guidelines for 3D radiative tool selection; and 5) improve atmospheric science education in 3D RT. Results from the two completed phases of I3RC have been presented in two workshops and are expected to guide improvements in both remote sensing and radiative energy budget calculations in cloudy atmospheres.
TL;DR: In this article, the authors present a comprehensive research program at the European Centre for Medium-Range Weather Forecasts (ECMWF) for modeling and assimilation of humidity, clouds, and precipitation.
Abstract: Several new types of satellite instrument will provide improved measurements of Earth's hydrological cycle and the humidity of the atmosphere. In an effort to make the best possible use of these data, the modeling and assimilation of humidity, clouds, and precipitation are currently the subjects of a comprehensive research program at the European Centre for Medium-Range Weather Forecasts (ECMWF). Impacts on weather prediction and climate reanalysis can be expected. The preparations for cloud and rain assimilation within ECMWF's four-dimensional variational data assimilation system include the development of linearized moist physics, the development of fast radiative transfer codes for cloudy and precipitating conditions, and a reformulation of the humidity analysis scheme. Results of model validations against in situ moisture data are presented, indicating generally good agreement—often to within the absolute calibration accuracy of the measurements. Evidence is also presented of shortcomings in ECMWF's h...
TL;DR: In this paper, the authors evaluated CCMs with the presented framework to increase confidence in predictions of stratospheric ozone change and found that the proposed framework increased the confidence in predicting ozone change.
Abstract: Evaluating CCMs with the presented framework will increase our confidence in predictions of stratospheric ozone change.
University of Washington1, Met Office2, Goddard Space Flight Center3, University of Alabama in Huntsville4, Max Planck Society5, National Oceanic and Atmospheric Administration6, Lille University of Science and Technology7, University of Maryland, Baltimore8, Langley Research Center9, University of Maryland, Baltimore County10
TL;DR: In this paper, the authors outline a practical strategy for achieving an observationally based quantification of direct climate forcing by anthropogenic aerosols using satellite observations coordinated with sub-orbital remote and in situ measurements and with chemical transport models.
Abstract: This document outlines a practical strategy for achieving an observationally based quantification of direct climate forcing by anthropogenic aerosols. The strategy involves a four-step program for shifting the current assumption-laden estimates to an increasingly empirical basis using satellite observations coordinated with suborbital remote and in situ measurements and with chemical transport models. Conceptually, the problem is framed as a need for complete global mapping of four parameters: clear-sky aerosol optical depth δ, radiative efficiency per unit optical depth E, fine-mode fraction of optical depth ff, and the anthropogenic fraction of the fine mode faf. The first three parameters can be retrieved from satellites, but correlative, suborbital measurements are required for quantifying the aerosol properties that control E, for validating the retrieval of ff, and for partitioning fine-mode δ between natural and anthropogenic components. The satellite focus is on the “A-Train,” a constellation of six spacecraft that will fly in formation from about 2005 to 2008. Key satellite instruments for this report are the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) radiometers on Aqua, the Ozone Monitoring Instrument (OMI) radiometer on Aura, the Polarization and Directionality of Earth's Reflectances (POLDER) polarimeter on the Polarization and Anistropy of Reflectances for Atmospheric Sciences Coupled with Observations from a Lidar (PARASOL), and the Cloud and Aerosol Lider with Orthogonal Polarization (CALIOP) lidar on the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). This strategy is offered as an initial framework—subject to improvement over time—for scientists around the world to participate in the A-Train opportunity. It is a specific implementation of the Progressive Aerosol Retrieval and Assimilation Global Observing Network (PARAGON) program, presented earlier in this journal, which identified the integration of diverse data as the central challenge to progress in quantifying global-scale aerosol effects. By designing a strategy around this need for integration, we develop recommendations for both satellite data interpretation and correlative suborbital activities that represent, in many respects, departures from current practice
TL;DR: In this paper, structural uncertainty introduced unintentionally through dataset construction choices is discussed, as is the question of how it needs to be reduced through future coordinated observing systems with long-term monitoring as a driver, enabling explicit calculation.
Abstract: Historically, meteorological observations have been made for operational forecasting rather than long-term monitoring purposes, so that there have been numerous changes in instrumentation and procedures. Hence to create climate quality datasets requires the identification, estimation, and removal of many nonclimatic biases from the historical data. Construction of a number of new tropospheric temperature climate datasets has highlighted previously unrecognized uncertainty in multidecadal temperature trends aloft. The choice of dataset can even change the sign of upper-air trends relative to those reported at the surface. So structural uncertainty introduced unintentionally through dataset construction choices is important and needs to be understood and mitigated. A number of ways that this could be addressed for historical records are discussed, as is the question of How it needs to be reduced through future coordinated observing systems with long-term monitoring as a driver, enabling explicit calculation...
TL;DR: DOTSTAR (Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region) is an international research program conducted by meteorologists in Taiwan partnered with scientists at the Hurricane Research Division (HRD) and the National Centers for Environmental Prediction (NCEP) of the National Oceanic and Atmospheric Administration (NOAA).
Abstract: DOTSTAR (Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region) is an international research program conducted by meteorologists in Taiwan partnered with scientists at the Hurricane Research Division (HRD) and the National Centers for Environmental Prediction (NCEP) of the National Oceanic and Atmospheric Administration (NOAA). The experiment is based on successful surveillance missions conducted in the Atlantic with NOAA's Gulfstream-IV jet aircraft. During the experiment, GPS dropwindsondes are released from a jet aircraft flying above 42000 ft in and around tropical cyclones approaching Taiwan to collect critical meteorological data for improving the analysis and the prediction of typhoons. After one-year of training, development and installation of all the needed software and hardware in the aircraft, the DOTSTAR research team initiated typhoon surveillance in 2003. Two missions (in Typhoons Dujuan and Melor) were conducted successfully,and seven or eight missions are expected to be conducted annually during the 2004 and 2005 typhoon seasons. The current manuscript provides an overview of the scientific objectives of DOTSTAR including operational plans, organization, data management, and data archiving. Preliminary results of the two missions in the first season in 2003 are presented. The experiment marks the beginning of typhoon surveillance in the western North Pacific and is expected to yield impressive improvements in typhoon research, observations and forecasting.
TL;DR: A gridded dataset of historical daily precipitation for South America is now available to the public as mentioned in this paper, which is a substantial improvement over what heretofore has been easily accessible because it contains data from numerous sources.
Abstract: Agridded dataset of historical daily precipitation for South America is now available to the public. We believe this dataset is a substantial improvement over what heretofore has been easily accessible because it contains data from numerous sources. Th ese data have been combined in a simple manner into daily 1° and 2.5° gridded fi elds for the period 1940–2003. Th e data should help to improve our understanding of precipitation variability, a fundamental and diffi cult problem of meteorology and climatology. Rapid spatial and temporal variability of precipitation, even in the absence of topography, makes diagnosis of the regionalto large-scale component extremely challenging. An accurate depiction of precipitation is a fi rst-order requirement for climate studies and model validation. Research into the causes of precipitation variability is seriously impeded by a frequent lack of adequate observational data. A few scattered observations, some of which may be missing at any given time, are unlikely to refl ect actual precipitation behavior. Th ese and other problems, including timeliness of station reports and a nearly complete lack of coverage over the oceans, have prompted a large research eff ort into estimating precipitation via satellite retrievals. Estimates derived from satellite measurements have proved immensely valuable in fi lling gaps in direct observations, and their accuracy improves as research continues. Nonetheless, gauge-based measurements of good quality and suffi cient density provide the most accurate estimate of precipitation over a given area. Further, satellite research has introduced the additional need for gauge-based observations to validate and calibrate the retrievals.
TL;DR: The Shared Mobile Atmospheric Research and Teaching (SMART) radar coalition as mentioned in this paper built the first mobile C-band Doppler weather radar in the United States and also successfully deployed a mobile Cband dual-Doppler network in a landfalling hurricane, which marked the beginning of an era in which high temporal and spatial resolution precipitation and dual-doppler wind data over mesoscale regions can be acquired from mobile ground-based platforms during extreme heavy rain and high-wind events.
Abstract: A group of scientists from three universities across two different states and from one federal research laboratory joined together to build and deploy two mobile C-band Doppler weather radars to enhance research and promote meteorological education. This 5-yr project led to the development of the Shared Mobile Atmospheric Research and Teaching (SMART) radar coalition that built the first mobile C-band Doppler weather radar in the United States and also successfully deployed the first mobile C-band dual-Doppler network in a landfalling hurricane. This accomplishment marked the beginning of an era in which high temporal and spatial resolution precipitation and dual-Doppler wind data over mesoscale (∼100 km) regions can be acquired from mobile ground-based platforms during extreme heavy rain and high-wind events. In this paper, we discuss the rationale for building the mobile observing systems, highlight some of the challenges that were encountered in creating a unique multia-gency coalition, provid...
TL;DR: CoCoRaHS as discussed by the authors is a community collaborative Rain, Hail, and Snow Network that was created to collect rain and hail data from the citizens of a small portion of Fort Collins, Colorado, and a similar storm over the grasslands of northeastern Colorado.
Abstract: T he Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS) originated in the aft ermath of a fl ash-fl ood storm that dropped more than 12-in. of rain over a small portion of Fort Collins, Colorado, on 28 July 1997, and a similar storm the following evening over the grasslands of northeastern Colorado. Th ese fl oods were responsible for several fatalities and at least $200 million in property damage. Neither event would have been accurately recorded by existing networks of offi cial weather stations. National Weather Service (NWS) radar also failed to assess the severity of these storms (Kelsch 1998a,b; Petersen et al. 1999). However, when the citizens of these areas were asked to help, they enthusiastically provided scientists with a wealth of information from their own backyard observations. Th ese data eventually resulted in the very accurate mapping of precipitation from the Fort Collins fl ash fl ood that continues to be used by engineers, hydrolo-gists, weather forecasters, city planners, emergency managers, attorneys, teachers, historians, and many others for such applications as flood forecasting, drought monitoring, verifi cation of radar-estimated precipitation, and climate trends. Encouraged by the enthusiastic public response, versity (CSU) in Fort Collins began mobilizing a network of citizen rain and hail observers in the spring of 1998. Th e initial plans targeted teachers and students from all grades in Fort Collins. However, unexpected free publicity from local media spread the word to the general public. Within a matter of days over 150 people volunteered, including students from nearly 40 schools in the region and interested adults. What started as a collaborative data-collection venture has developed into an exciting community based science education program that includes classroom presentations, fi eld trips, training sessions, picnics, and informal seminars. CoCoRaHS now includes over 1000 active volunteers across Colorado (see Table 1), as well as several hundred in Nebraska, Wyoming, Kansas, and New Mexico. They range in age from 6 to 80-plus years. Th is diversity of age and background of participants is one of the true TABLE 1. Level of participation in the CoCoRaHS network (Colorado only) from 1998 through Oct 2004. Active volunteers are defined as observers who submit at least five observations between 1 Jun and 31 Oct for the calendar year. In addition to the numbers below, several hundred more observers participated for a few weeks but have not remained active.
TL;DR: The Advanced Hydrologic Prediction Service (AHPS) as discussed by the authors was established by the National Oceanic and Atmospheric Administration (NOAA) National Weather Service (NWS) to meet the need for more precise flash-flood forecast information.
Abstract: The National Oceanic and Atmospheric Administration (NOAA) National Weather Service (NWS) Advanced Hydrologic Prediction Service (AHPS) program was established to meet our nation's need for more precise flash-flood forecast information. AHPS uses NOAA investments in remote sensing, precipitation forecasts, climate predictions, data automation, hydrologic science, and operational forecast system technologies. AHPS establishes a pathway for the infusion of new verified science and technology, and expands the use of NWS climate, weather, and water analyses and information products. State-of-the-art science is used for improved operational forecasting of floods, and drought conditions. The objective is to deliver more precise forecast information over greater temporal scales (hours, days, and months) and to depict the magnitude and certainty of occurrence for events ranging from droughts to floods. The AHPS program improves flash-flood forecasts, and provides ensemble streamflow forecasting and flood...