README FILE FOR DAILY GLOBAL HISTORICAL CLIMATOLOGY NETWORK (GHCN-DAILY) 
Version 3.11


MFLAG1     is the measurement flag.  There are ten possible values:

           Blank = no measurement information applicable
           B     = precipitation total formed from two 12-hour totals
           D     = precipitation total formed from four six-hour totals
	   H     = represents highest or lowest hourly temperature
	   K     = converted from knots 
	   L     = temperature appears to be lagged with respect to reported
	           hour of observation 
           O     = converted from oktas 
	   P     = identified as "missing presumed zero" in DSI 3200 and 3206
           T     = trace of precipitation, snowfall, or snow depth
	   W     = converted from 16-point WBAN code (for wind direction)

QFLAG1     is the quality flag.  There are fourteen possible values:

           Blank = did not fail any quality assurance check
           D     = failed duplicate check
           G     = failed gap check
           I     = failed internal consistency check
           K     = failed streak/frequent-value check
	   L     = failed check on length of multiday period 
           M     = failed megaconsistency check
           N     = failed naught check
           O     = failed climatological outlier check
           R     = failed lagged range check
           S     = failed spatial consistency check
           T     = failed temporal consistency check
           W     = temperature too warm for snow
           X     = failed bounds check
	   Z     = flagged as a result of an official Datzilla 
	           investigation

SFLAG1     is the source flag.  There are twenty eight possible values 
(including blank, upper and lower case letters):

           Blank = No source (i.e., data value missing)
           0     = U.S. Cooperative Summary of the Day (NCDC DSI-3200)
           6     = CDMP Cooperative Summary of the Day (NCDC DSI-3206)
           7     = U.S. Cooperative Summary of the Day -- Transmitted 
	           via WxCoder3 (NCDC DSI-3207)
           A     = U.S. Automated Surface Observing System (ASOS) 
                   real-time data (since January 1, 2006)
	   a     = Australian data from the Australian Bureau of Meteorology
           B     = U.S. ASOS data for October 2000-December 2005 (NCDC 
                   DSI-3211)
	   b     = Belarus update
	   E     = European Climate Assessment and Dataset (Klein Tank 
	           et al., 2002)	   
           F     = U.S. Fort data 
           G     = Official Global Climate Observing System (GCOS) or 
                   other government-supplied data
           H     = High Plains Regional Climate Center real-time data
           I     = International collection (non U.S. data received through
	           personal contacts)
           K     = U.S. Cooperative Summary of the Day data digitized from
	           paper observer forms (from 2011 to present)
           M     = Monthly METAR Extract (additional ASOS data)
	   N     = Community Collaborative Rain, Hail,and Snow (CoCoRaHS)
	   Q     = Data from several African countries that had been 
	           "quarantined", that is, withheld from public release
		   until permission was granted from the respective 
	           meteorological services
           R     = NCDC Reference Network Database (Climate Reference Network
	           and Historical Climatology Network-Modernized)
	   r     = All-Russian Research Institute of Hydrometeorological 
	           Information-World Data Center
           S     = Global Summary of the Day (NCDC DSI-9618)
                   NOTE: "S" values are derived from hourly synoptic reports
                   exchanged on the Global Telecommunications System (GTS).
                   Daily values derived in this fashion may differ significantly
                   from "true" daily data, particularly for precipitation
                   (i.e., use with caution).
	   s     = China Meteorological Administration/National Meteorological Information Center/
	           Climatic Data Center (http://cdc.cma.gov.cn)
           T     = SNOwpack TELemtry (SNOTEL) data obtained from the Western
	           Regional Climate Center
	   U     = Remote Automatic Weather Station (RAWS) data obtained
	           from the Western Regional Climate Center	   
	   u     = Ukraine update	   
	   W     = WBAN/ASOS Summary of the Day from NCDC's Integrated 
	           Surface Data (ISD).  
           X     = U.S. First-Order Summary of the Day (NCDC DSI-3210)
	   Z     = Datzilla official additions or replacements 
	   z     = Uzbekistan update
	   
	   When data are available for the same time from more than one source,
	   the highest priority source is chosen according to the following
	   priority order (from highest to lowest):
	   Z,R,0,6,X,W,K,7,F,B,M,r,E,z,u,b,a,s,G,Q,I,A,N,T,U,H,S