Advisers to the Nation on Science, Engineering, and Medicine
National Academy of Sciences
National Academy of Engineering
Institute of Medicine
National Research Council
Board on Atmospheric Sciences and Climate
Commission on Geosciences, Environment, and Resources
September 6, 2000
Gregory W. Withee
National Environmental Satellite, Data, and Information Service
National Oceanic and Atmospheric Administration 1335 East-West Highway Silver Spring, MD 20910-3283
Dear Mr. Withee:
This letter report is in response to a request from you to build upon the recommendations contained in the report Reconciling Observations of Global Temperature Change (NRC, 2000a) by the National Research Council's (NRC) Panel on Reconciling Temperature Observations (RTO). It addresses specific concerns expressed by the National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite, Data, and Information Service (NESDIS) regarding climate-quality, upper air temperature observations over the next decade provided by the four future Polar Orbiting Environmental Satellites (POES) spacecraft flights and the present in-situ systems. The panel was asked to provide findings and recommendations that can assist NOAA/NESDIS in optimizing their ability to monitor long-term upper air temperature trends.
At the present time, atmospheric observations are made primarily for the purpose of weather monitoring and prediction. However, the public and the scientific community are increasingly recognizing the value of stable, homogeneous, long-term climate datasets which can be used to reliably determine departures from normal (anomalies) and to detect long-term changes. To the extent possible, information about state variables of the atmosphere (e.g., temperature, humidity) is being used to detect climate change, to better understand the fundamental nature of climate variability, and to predict interannual and longer-term climate variations. However, such climate-related uses of the observations are hampered by problems associated with the precision, continuity, spatio-temporal coverage, and documentation of the current meteorological observations. Climate change research and monitoring often require the detection of very small changes against a naturally noisy background.
NESDIS has expressed an interest in instituting changes that will enhance the production of what we shall refer to as Climate Data Records (CDR) to address the aforementioned concerns. A CDR is defined in NRC (2000b) as a time series in which the often multiple sources of error and noise are accounted for, so that it is characterized by stable, high quality data with quantified error characteristics. A CDR requires considerable refinement of the raw data, generally blending multiple data streams together. These streams may come from multiple copies of the same sensor, or they may be ancillary data fields that are used to “adjust” the primary data stream. Thorough analysis of sensor performance and improved processing algorithms are also required, as well as quantitative estimates of spatial and temporal errors. A CDR is suitable for studying interannual-to-decadal-scale climate variability.
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