Atmos Composition
Product Summary
Data Set Short Name: MERG Data Set Long Name: NCEP/CPC 4km Global (60N - 60S) IR Dataset Data Set Version: 1 Data Set Creator: Climate Prediction Center/NCEP/NWS Platform: GEOSTATIONARY SATELLITES Temporal Resolution: 30 min Temporal Coverage: 2000-02-07 - present Parameters: CYCLONES, HURRICANES, MONSOONS, STORMS, TYPHOONS Data Holdings Page: View |
Product Description
The Climate Prediction Center/NCEP/NWS is now making available via anonymous ftp (in digital form) globally-merged (60N-60S) pixel-resolution IR brightness temperature data (equivalent blackbody temps), merged from all available geostationary satellites (GOES-8/10, METEOSAT-7/5 & GMS). The availability of data from METEOSAT-5, which is located at 63E at the present time, yields a unique opportunity for total global (60N-60S) coverage. The global IR composites available are now available in digital form for every 1/2 hour via a weekly rotating file. The data have been corrected for "zenith angle dependence", i.e. IR temperatures for locations far from satellite nadir are erroneously cold due to a combination of geometric effects and radiometric path extinction effects. This correction allows for the merging of the IR data from the various geostationary satellites with greatly reduced discontinuities at their boundaries. Some residual differences among the data exist since the IR channels aboard the various spacecraft have slightly different characteristics and no intercalibration among the sensors has been performed. We are in the process of performing such an intercalibration, although this effect is considerably smaller than the zenith angle effects. The data availability are delayed by 3 days from real-time to abide by international data exchange agreements between NOAA and EUMETSAT (the METEOSAT data providers). We are working on a web page that will have an image browse capability (at reduced resolution) along with tools to make data downloading easier. The data are too voluminous (33 MB per 1/2 hour) to service requests for historical data or spatial subsets of the data. However, the National Climatic Data Center (NCDC) has agreed to be the official archive & distribution center for these data, although the infrastructure for this activity is not yet in place. Please note that, at present, we are using a makeshift assortment of existing in-house hardware to perform these tasks and, while reliable over the course of the past few months, is not optimal for the tasks at hand. We are in the process of procuring a dedicated system for this activity which should be installed within the next 2-3 months. |
