Adequacy of Climate Observing Systems (1999) / Chapter Skim
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Pages 7-28
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From page 7... ...
. The 1997-1998 El Nino, one of the most publicized examples of recent natural climate variability, markedly modified rainfall patterns, creating intense droughts in some regions and devastating floods in others.
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From page 8... ...
Several countries, including the United States, developed and ratified the FCCC on the basis of scientific consensus on the likelihood of future climate change contained in the IPCC's First Assessment Report (IPCC, 19901. A major objective of the FCCC is the stabilization of atmospheric greenhouse gas concentrations at a level that would prevent dangerous anthropogenic interference with the climate system.
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From page 9... ...
Examining the ways humans depend on or respond to climate helps identify the physical climate variables most important to sustaining life and human wellbeing. Food production and agricultural systems depend on local air temperature, precipitation, and the solar radiation during the growing season.
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From page 10... ...
Long-term changes may involve only a slow rise in sea level, but water levels can rise rapidly during storm surges, inundating coastal communities and low-lying areas. Human health depends directly on temperature and humidity, both of which contribute to heat stress and influence the transmission of infectious disease and the abundance of allergens.
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From page 11... ...
reflected solar radiation outgoing thermal radiation OCEANS sealevel M H sea surface temperature and salinity H M upper ocean temperature and salinity M H deep ocean temperature profile M M .
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From page 12... ...
Recently, patterns of the vertical distribution of temperature changes throughout the atmosphere and changing frequencies of intense rainfall over land have been used successfully to detect and attribute human-induced climate change. Many of the bolded variables in Table 1 are critical for confirming and interpreting results of the climate models.
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From page 13... ...
Precipitation is measured daily at 11,000 cooperative observing sites across the United States by volunteer observers using NOAA instruments. Minimum and maximum air temperatures and snow depth are measured at about half of these stations, and a few percent of the stations also record evaporation from evaporimeters during the growing season.
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From page 14... ...
The research community is developing other means to observe the vertical distribution of water vapor in the atmosphere, but it will be a number of years before climatic observations will be available. Sea surface temperatures are measured by ships of opportunity, several arrays of moored buoys, strategically deployed drifting buoys, coastal observing stations, and instrumentation on operational satellites.
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From page 15... ...
, but these data are of limited use for monitoring decadal changes because of many inadequately documented changes in locations and measurement methods (Karl and Knight, 19971. Sea level pressure measurements have a long history and can be used for approximating winds using first order physical relationships.
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From page 16... ...
Any data base obtained from an observing system not specifically designed and operated for climate observing purposes is likely to contain inhomogeneities that must be removed before the data can be used with confidence for climate analyses. For any network or instrument whose mission is documentation of weather and climate, the following ten climate monitoring principles should apply (Karl et al., 1995~.
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From page 17... ...
Changes in observing times will adversely affect time series. Without adequate transfer functions, spatial changes and spatially dependent changes will adversely affect the mapping of climatic elements.
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From page 18... ...
These agencies operate a large number of observing and data management systems used by the scientific community, but no agency has the mission or assumes responsibility to assess routinely the adequacy of these data for analyzing decadal climate changes and variability. A reliable and stable climate observing system is possible only if there are measures that assess its actual climate monitoring performance (i.e., near-real time assessment of data quality, continuity, and homogeneity)
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From page 19... ...
Existing observing systems for the relevant climate variables can be assessed using the ten principles for climate monitoring systems described above. Table 2 provides a summary of U.S.
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From page 20... ...
20 ADEQUACY OF CLIMATE OBSERVING SYSTEMS TABLE 2 Evaluation of capability to deliver data suitable for detecting climate variations and changes on multi-decadal time scales. PRINCIPLES 2 3 4 5 6 7 8 9 10 Temperature Surface land -- -- -- A A -- A -- A A Sea surface -- -- -- -- A -- -- -- Subsurface ocean -- -- -- -- A -- -- A A Vertical distribution -- -- -- -- A Water Land precipitation -- -- -- -- A Ocean precipitation Streamflow Evapo~anspiration Ground water Snow cover/depth Lakes and reservoirs Atmospheric water vapor Sea level -- -- A A A -- -- A -- A Sea ice -- -- -- -- A Sea Level Pressure arid -- -- -- -- A Winds Terrestrial Ecosystems Land cover change -- -- -- -- A -- -- A A Biogeochemis~y -- -- -- -- A -- -- A A _ _ .
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From page 21... ...
Historical Climatology Network. This figure shows the number of stations in the U.S.
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From page 22... ...
SOURCE: NCDC,NOAA. COADS Reports per Year 3,000,000 2,500,000 2,000,000 1,500,000 O 1850 1900 1950 2000 1,000,000 500,000 FIGURE 4 The Comprehensive Ocean/Atmosphere Data.
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From page 23... ...
1 ~ I~ 1 -0.60 -80 "0 0 40 Months, Before and~terSwilch 23 Minimum Temperature , "0 0 40 blortl=, Before end after Switch FIGURE 5 The effect of the change in instrumentation on the data for maximum, minimum, and range of temperatures of the Cooperative Weather Observer Network. These data represent the average time series of aggregated mean temperature differences referenced to the time of instrument change.
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From page 24... ...
Five systems of special concern and interest include those for marine surface air and sea surface temperatures, vertical distribution of atmospheric temperatures, precipitation, atmospheric water vapor, and sea level pressure and winds.
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From page 25... ...
Vertical Distribution of Atmospheric Temperatures: New techniques are emerging to support more highly detailed weather forecasts. As these new techniques are introduced, considerations of apparent redundancy and budget pressures could shrink substantially the radiosonde network, which has provided our current understanding of global temperature variability and change over the last half century (see Box 31.
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From page 26... ...
Atmospheric Water Vapor: Water vapor is the most important greenhouse gas, and changes in it play a very important role for quantifying the effect of the addition of anthropogenic greenhouse gases into the atmosphere. It is also critical to understanding changes in the hydrologic cycle of evaporation, precipi
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From page 27... ...
Sea Level Pressure and Winds: Managers of operational sea level pressure and wind measuring systems for weather forecasting continually change their practices to improve efficiency and accuracy. These changes have not been implemented in a manner that would allow the impact of change to be quantified in analyses.
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