DATA
SOURCE: River Forecast Centers ~5000 stations
per day, including ~1500 stations from the
Hydrologic Automated Data System, and Climate
Anomaly Data Base ~several hundred stations per day
RESOLUTION: 0.5 degree x 0.5 degree
DOMAIN: 20N - 60N; 140W - 60W
FORMAT: The format is sequential 32-bit IEEE
floating point created on a big_endian platform
(e.g. cray, sun, sgi and hp). The undefined
(missing) value is 9999.
WINDOW: Day 1 analysis is valid for the
window from 12Z on day 0 to 12Z on day 1; because of
report receipt timing, daily minima are available 1
day earlier than the maxima and the means.
ANALYSIS SCHEME: Modified Cressman (1959)
scheme (Glahn et al. 1985; Charba et al. 1992).
Minimum stations for analysis: 350. If the number of
stations is fewer than the minimum, the analysis is
not performed for that day.
QUALITY CONTROL: Climatological standard
deviation check. If a reported value is more than 4
standard deviations removed from the historical
distribution, the value is omitted from the
analysis.