Note: Effective November 2011, the GHCN-M version 3.1.0 dataset of monthly mean temperature replaced the GHCN-M version 3 monthly mean temperature dataset. Beginning with the October 2011 Global monthly State of the Climate Report, GHCN-M version 3.1.0 is used for NCDC climate monitoring activities, including calculation of global land surface temperature anomalies and trends.
For more information about this newest version, please see the Modifications to Pairwise Homogeneity Adjustment software to address coding errors and improve run-time efficiency.
This data set contains gridded mean temperature anomalies from the Global Historical Climatology Network-Monthly (GHCN-M) version 3 temperature data set. The gridded anomalies were produced from GHCN-M bias corrected data. Each month of data consists of 2,592 gridded data points produced on a 5° by 5° basis for the entire globe (72 longitude by 36 latitude grid boxes).
Gridded data for every month from January 1880 to the most recent month is available. The data are temperature anomalies in degrees Celsius. Each gridded value was multiplied by 100 and written to file as an integer. Missing values are represented by the value -9999.
The data are formatted by year, month, latitude and longitude. There are 72 longitude grid values per line, so there is one line for each of the 36 latitude bands. Longitude values are written from 180°W to 180°E, and latitude values from 90°N to 90°S. Data for each month is preceded by a label containing the month and year of the gridded data.
for year = begYear to endYear
for month = 1 to 12
format(2i5) month,year
for lat = 1 to 36 (85-90N,80-85N,...,80-85S,85-90S)
format(72i6) 180-175W,175-170W,...,170-175E,175-180E
This data set contains gridded precipitation anomalies calculated from the GHCN version 2 monthly precipitation data set. 2,064 homogeneity adjusted precipitation stations (from the U.S., Canada, and Former Soviet Union) were combined with a data set containing 20,590 raw precipitation stations throughout the world to create these gridded fields. Grid boxes with no homogeneity adjusted data, GHCN raw data was used to provide the greatest possible global coverage. Each month of data consists of 2,592 gridded data points produced on a 5° by 5° basis for the entire globe (72 longitude by 36 latitude grid boxes).
Gridded data for every month from January 1900 to the most recent month is available. The data are precipitation anomalies in millimeters. Each gridded value was multiplied by 100 and written to file as an integer. Missing values are represented by the value -32768.
The data are formatted by year, month, latitude and longitude. There are twelve longitude grid values per line, so there are 6 lines (72/12 = 6) for each of the 36 latitude bands. Longitude values are written from 180°W to 180°E, and latitude values from 90°N to 90°S. Data for each month is preceded by a label containing the month and year of the gridded data.
for year = begYear to endYear
for month = 1 to 12
format(2i7) month,year
for lat = 1 to 36 (85-90N,80-85N,...,80-85S,85-90S)
format(12i7) 180-175W,175-170W,...,130-125W,125-120W
format(12i7) 120-115W,175-170W,...,70-65W,65-60W
format(12i7) 60-55W,55-50W,...,10-5W,5-0W
format(12i7) 0-5E,5-10E,...,50-55E,55-60E
format(12i7) 60-65E,65-70E,...,110-115E,115-120E
format(12i7) 120-125E,125-130E,...,170-175E,175-180E
These datasets were created from station data using the Anomaly Method, a method that uses station averages during a specified base period from which the monthly/seasonal/annual departures can be calculated. Anomalies were calculated on a monthly basis for all adjusted stations having at least 20 years of data in the 1961–1990 base period. Station anomalies were then averaged within each 5° by 5° grid box to obtain the gridded anomalies. For those grid boxes without adjusted data, anomalies were calculated from the raw station data using the same technique.
After the creation of the 5° by 5° anomaly grid, the grid boxes are averaged across the globe using cosine weighting to obtain the global average temperature and precipitation anomaly for each month. The global temperature anomalies can be accessed via the Global Surface Temperature Anomalies page.
We developed these gridded data sets to produce the most accurate time series possible. However, this required that we treat months and grid boxes independently through time. The use of these data sets is most appropriate for analyzing the change in temperature within a particular grid box, or set of grid boxes, over a span of years. If one is more interested in analyzing temperature changes within individual years, e.g., the change in temperature between February and March, 1908, or between two regions in 1908, we recommend that the GHCN station data be used directly.
Please note that the anomalies for all files are with respect to the 1961–1990 base period, with the exception of the Merged Land and Ocean Surface Temperature (MLOST). The MLOST gridded anomalies are with respect to the 1971–2000 base period.
Files have been compressed using gzip.
GHCN version 3 Land Temperature Anomalies grid file:
grid-mntp-1880-current-v3.dat.gz
Land and Ocean Temperature Anomalies grid file using GHCN version 3:
ncdc-merged-sfc-mntp.dat.gz
GHCN version 2 Land Precipitation Anomalies grid file:
grid_prcp_1900-current.dat.gz
FTP Site : ftp.ncdc.noaa.gov
Login Name : anonymous
Password : your email address
Enter : bin
GHCN version 3 Land Temperature Anomalies grid file
Directory : /pub/data/ghcn/v3/grid/
Enter : get grid-mntp-1880-current-v3.dat.gz
Land and Ocean Temperature Anomalies grid file using GHCN version 3
Directory : /pub/data/ghcn/blended/
Enter : get ncdc-merged-sfc-mntp.dat.gz
GHCN version 2 Land Precipitation Anomalies grid file
Directory : /pub/data/ghcn/v2/grid/
Enter : get grid_prcp_1900-current.dat.gz
PLEASE NOTE: On May 2, 2011, NCDC transitioned to GHCN-M v3 as the official land component of its global temperature monitoring efforts. GHCN-M v2 mean temperature dataset will continue to be updated through May 30, 2011, but no support for this version of the dataset will be provided.
GHCN-M version 2 Land Temperature Anomalies grid file:
grid-mntp-1880-current-v2.dat.gz
Land and Ocean Temperature Anomalies grid file using GHCN-M version 2:
ncdc_blended_merg53v3b.dat.gz
FTP Site : ftp.ncdc.noaa.gov
Login Name : anonymous
Password : your email address
Enter : bin
GHCN version 2 Land Temperature Anomalies grid file
Directory : /pub/data/ghcn/v2/grid/
Enter : get grid-mntp-1880-current-v2.dat.gz
Land and Ocean Temperature Anomalies grid file using GHCN version 2
Directory : /pub/data/ghcn/blended/usingGHCNMv2/
Enter : get ncdc_blended_merg53v3b.dat.gz
For all climate questions, please contact the National Climatic Data Center's Climate Services and Monitoring Division:
Climate Services and Monitoring Division
http://lwf.ncdc.noaa.gov/temp-and-precip/ghcn-gridded-products.php