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Documentation for gridded climate data for 1961-90 and
scenarios for 2010-39 and 2040-69 periods
1961-1990 baseline climate
The file ‘Normals61.txt’ contains gridded monthly mean values for daily maximum and
minimum air temperature and total precipitation for the 1961-1990 period. These data
were constructed by interpolating monthly climate data as a function of latitude,
longitude and elevation using ANUSPLIN (Hutchinson, 2000). ANUSPLIN uses thin
plate smoothing splines as the interpolation technique (Hutchinson, 1995). Any stations
with 5 or more years of record were used (Environment Canada, 1994). The grid is 500
arc seconds and was developed using a Digital Elevation Model (DEM) data, based on
the National Topographic Series 1:250,000 topographic data. For details of these
particular Canadian applications see McKenney et al. (2001) (see also Price et al. 2000).
File Name: Normals61.ZIP
File Structure: Comma-delimited text file, compressed using WinZip. Variables on the
file are as follows:
Latitude and Longitude (decimal degrees)
12 monthly values (Jan. – Dec.) for average maximum temperature, ºC
12 monthly values (Jan. – Dec.) for average minimum temperature, ºC
12 monthly values (Jan. – Dec.) for total precipitation, mm
File Size: Zipped: 4.4 Mb; decompressed 12.7 Mb
Climate scenarios – 2010-2039 and 2040-2069
Climate change scenarios were based on the first generation coupled Canadian
General Circulation Model, greenhouse gas with aerosols simulation 1 (CGCMI GA1).
Mean monthly changes in temperature and in precipitation ratios from 1961-1990 values
were interpolated to the same 500 arc second grid as above using ANUSPLIN with only
latitude and longitude as predictor variables. The interpolated change values were then
applied to the gridded 1961-1990 normals in ‘Normals61.txt’.
File Names:
Normals10.ZIP (Monthly climate normals for 2010-2039 period)
Normals40.ZIP (Monthly climate normals for 2040-2069 period)
File Structure: Same as ‘Normals61.ZIP’
File Size:
Similar to ‘Normals61.ZIP’
Calculation of agro-climatic indices
Agroclimatic indices were computed using the gridded monthly values as input
data. Initially, 365 daily values of average maximum temperature and of average
minimum temperature were generated from monthly average values using the Brooks
sine wave interpolation procedure (Brooks, 1943). Average daily values for precipitation
were generated by dividing the monthly values by the number of days in the month. The
average daily values were then used to compute the following indices:
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Growing degree-days above 5ºC (GDD):
GDD were computed by calculating the amount by which average daily mean
temperature (Tmean) exceeded 5.0C and summing these values from the time when Tmean
first exceeded 5.0C in spring until the last date of Tmean exceeded 5.0C in fall. While
this procedure will result in some differences from GDD computed from daily values
rather than averages (since averages may include days when temperatures were below the
base value in the spring and fall periods), it has been commonly accepted as being of
sufficient accuracy (Chapman and Brown 1978)
Effective Growing Degree-Days (EGDD):
EGDD are used as a primary climate classifier in the suitability rating system for
spring-seeded small grains and are determined based on the method described in the
Working Group report (Agronomics Interpretations Working Group, 1995). GDD were
summed from 10 days after Tmean 5.0C in spring to the average date of the first fall
frost (0C), and a daylength factor was applied to compensate for increased effectiveness
of GDD in maturing cereal crops in northern latitudes. Average fall frost dates were
estimated from monthly temperature normals, elevation and astronomical data as
described by Sly et al. (1971). Daylength (N) and solar radiation at the top of the
atmosphere (Qo) were estimated from latitude and time of year using procedures
described by Robertson and Russelo (1968).
Potential Evapotranspiration (PE) and Precipitation Deficit (DEFICIT):
Average daily PE was determined by calculating Latent evaporation (LE) from
daily temperatures and solar radiation at the top of the atmosphere, using Baier and
Robertson (1965) Formula I and converting LE to PE by using the conversion factor of
0.086. Average daily DEFICIT was calculated by subtracting average daily precipitation
(P) from PE. Daily DEFICIT and PE values were accumulated over periods shown
below.
File Names:
Indices61.ZIP, Indices10.ZIP and Indices40.ZIP. These files contain the
gridded indices for the 1961-90, 2010-39 and 2040-69 periods,
respectively.
File Structure: Comma-delimited text file, compressed using WinZip.
Variables on the file are as follows:
Latitude (decimal degrees)
Longitude (decimal degrees)
GDD (Celsius)
StartGDD (Starting date for accumulating GDD, calendar day)
StopGDD (Ending date for accumulating GDD, calendar day)
EGDD (Celsius)
StartEGDD (Starting date for accumulating EGDD, calendar day)
StopEGDD (Ending date for accumulating EGDD, calendar day)
DEFICIT1 (Accumulated over same period as GDD, mm)
PE1 (Accumulated over same period as GDD, mm)
DEFICIT2 (Positive values only of PE – P accumulated over same period
as EGDD, mm)
PE2 (Accumulated over same period as EGDD, mm)
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File Size:
Zipped: 0.9 Mb; decompressed: 3.3 Mb
Questions about the data or feedback should be directed to:
Andrew Bootsma, Agro-climatologist
Agriculture and Agri-Food Canada
Eastern Cereal and Oilseed Research Centre
K.W. Neatby Bldg., Rm. 4129B
960 Carling Ave.
Ottawa ON CANADA K1A 0C6
Tel: (613) 759-1526
Fax: (613) 759-1924
E-mail: BootsmaA@agr.gc.ca
or
Dan McKenney (PhD)
Chief, Landscape Analysis and Applications
Canadian Forest Service
1219 Queen Street East
Sault Ste. Marie, Ontario
CANADA P6A 2E5
Ph 705-759-5740 ext 2316
Fax 705-759-5700
Email dmckenne@nrcan.gc.ca
Disclaimer:
These data are available free for public use but remain copyright of Agriculture and AgriFood Canada (AAFC) and Natural Resources Canada (NRCan). The information has
been obtained from a variety of sources and while efforts have been undertaken to assure
its accuracy, it is provided without warranty as a public service. Any decision taken based
on the information contained within these data files is the sole responsibility of the person
taking the decision.
REFERENCES
Agronomics Interpretations Working Group. 1995. Land Suitability Rating System for
Agricultural Crops: 1. Spring-seeded small grains. Edited by W.W. Pettapiece.
Tech. Bull. 1995-6E. Centre for Land and Biological Resources Research,
Agriculture and Agri-Food Canada, Ottawa, 90 pp., 2 maps.
Baier, W. and Robertson, G.W. 1965. Estimation of latent evaporation from simple
weather observations. Can. J. Plant Sci. 45: 276-284.
Brooks, C.E.P. 1943. Interpolation tables for daily values of meteorological elements.
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Quart. J. Royal Meteorol. Soc. 69: 160-162.
Chapman, L.J. and Brown, D.M. 1978. The Climates of Canada for Agriculture. Canada
Land Inventory Report No. 3. Revised 1978. Environment Canada, Lands
Directorate, 24 pp.
Environment Canada 1994. Canadian Monthly Climate Data and 1961-1990 Normals on
CD-ROM, Version 3.0E. Environment Canada, Atmospheric Environment
Service, Downsview, Ontario.
Hutchinson, M.F. 1995. Interpolating mean rainfall using thin plate smoothing splines.
Int. J. Geographical Information Systems 9: 385-403
Hutchinson, M.F. 2000. ANUSPLIN Version 4.1 User Guide. Centre for Resource and
Environmental Studies, Australian National University, Canberra ACT 0200,
Australia.
McKenney, D.W., Hutchinson, M.F., Kesteven, J. and Venier, L. 2001. Canada's plant
hardiness zones revisited using modern climate interpolation techniques. Can J.
Plant Science 81:129-143
Price, D., McKenney, D.W., Nalder, I., Hutchinson, M.F. and Kestevan, J. 2000. A
comparison of two statistical methods for interpolating monthly mean climate.
Ag. And Forest. Met. 101:81-94.
Robertson, G.W. and Russelo, D.A. 1968. Astrometeorological estimator for estimating
time when sun is at any elevation, elapsed time between the same elevations in
the morning and afternoon, and hourly and daily values of solar energy, Qo. Tech.
Bull. 14, Agrometeor. Section, Plant Research Inst., Canada Dept. Agriculture, 22
pp.
Sly, W., Robertson, G.W. and Coligado, M.C. 1971. Estimation of probable dates of
temperatures near freezing from monthly temperature normals, station elevation,
and astronomical data. Canada Department of Agriculture, Research Branch,
Plant Research Institute, Agrometeorology Section, Ottawa, Tech. Bull. 79, 21 pp.