of NDP-026C
Extended Edited Synoptic Cloud Reports from Ships and Land Stations Over the Globe, 1952-1996
Download the Data and ASCII Documentation files of NDP-026C
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of NDP-026C
PLEASE NOTE: On March 8, 2002 this page and the global cloudiness data set were updated to reflect the addition of 12 monthly files of ship reports for 1997. Previously, the ship data extended only through 1996. Neither the name of the NDP-026C database or specific details included in associated documentation files will be changed to reflect these additional data until some point in the future when additional land and ocean data are added.
S. G. Warren, Dept. of Atmospheric Sciences, University of Washington This database contains surface synoptic weather reports for the entire globe, gathered from various available data sets. The reports were processed, edited, and rewritten to provide a single dataset of individual observations of clouds, spanning the 46 years 1952-1997 for ship data and the 26 years 1971-1996 for land station data. In addition to the cloud portion of the synoptic report, each edited report also includes the associated pressure, present weather, wind, air temperature, and dew point (and sea surface temperature over oceans). This data set is called the "Extended Edited Cloud Report Archive" (EECRA).
Reports from the source data sets that did not meet certain quality control standards were rejected for the EECRA. Minor correctable inconsistencies within reports were edited for consistency. Cases of "sky obscured" were interpreted by reference to the present-weather code as to whether they indicated fog, rain, snow, or thunderstorm. Special coding was added to indicate probable nimbostratus clouds which are not specifically coded for in the standard synoptic code. Any changes made to an original report are also noted in the archived edited report so that the original report can be reconstructed if desired. This "extended edited cloud report" also includes the amounts, either inferred or directly reported, of low, middle, and high clouds, both overlapped and non-overlapped amounts. The relative lunar illuminance and the solar zenith angle associated with each report are also given, as well as an indicator that tells whether our recommended illuminance criterion was satisfied so that the "night-detection bias" for clouds can be minimized.
The EECRA contains over 73 million cloud observations from ships and 311 million from land stations. Each report is 80 characters in length. The archive consists of 865 files of edited synoptic reports, one file for each month of data for land and ocean separately, and 4 ancillary files which provide important information about reporting characteristics of the land stations. The 865 synoptic report files have been compressed using unix; their total size approaches 10 GB (over 30 GB when uncompressed).
This data set will be useful for applications such as: (1) development of user-defined cloud climatologies for particular subtypes of clouds, or for different temporal and spatial resolution than we have chosen for our atlases, (2) in comparison of satellite cloud retrievals with surface observations, to help diagnose difficulties in cloud identification from satellite, and (3) to relate formation of individual types of clouds to their meteorological environments.
Note:
If you're interested in the NDP-026C database, then you'll also want to read about its follow-up data product, NDP-026D.
Last updated 03/2005
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