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R Gommes, M Bernardi, F Nachtergaele, FAO J. Grieser, DWD/GPCC. WORKSHOP ON CLIMATIC ANALYSIS AND MAPPING FOR AGRICULTURE (14-17 June 2005, Bologna, Italy) . Why we need a new climate classification for agriculture (CCA). Some history... (1).
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R Gommes, M Bernardi, F Nachtergaele, FAO J. Grieser, DWD/GPCC WORKSHOP ON CLIMATIC ANALYSIS AND MAPPING FOR AGRICULTURE (14-17 June 2005, Bologna, Italy) Why we need a new climate classification for agriculture (CCA)
Some history... (1) Koeppen (1918-1936) and Trewartha (1968): threshold-based vegetation-oriented Ivanov (1948): threshold-based, sums of temperature, moisture index GKU = Annual rain / f [(annual t)2, annual RH]) desert: GKU<0.13; rainforest: GKU>1.5 Thornthwaite (1931): Precip. Effectiveness Ratio PER = 115 * [ inches rain / (Fahrenheit-10)]10/9 PEI = Sum monthly PER; TEI = Sum TER
Some history... (2) Thornthwaite (1948): introduces ET and Moisture Index monthly PE = 1.6 daylength (10 T / HI) a HI = (T / 5) 1.514 a = 0.49 + 0.017 HI + 0.00077 HI2 + etc. Budyko (1955) introduces radiation Seljaninov (1966-72): “agricultural classification” Vegetation v period defined as Tav day > 10C. Later “adjusted” with Drought Index GTKv = 10 Sum Rain/ SDD above 10C GTKv >1.5: need to drain GTKv <0.5 : need to irrigate Sasko, Kloskov, Papadakis, Botanists (Gaussen, de Martonne, Emberger), Lang, FAO (AEZ/LGP) etc.
The climate “complex” (286 Latin-American stations, average March data)
CCA philosophy Agronomically significant classifiers Avoidance of redundant classifiers Variability essential ingredient Organism independent but relevant for crops, animals, forest, diseases etc Hierarchical (e.g. mappable) and scale independent (global, topo, micro) Transparent links with other classifications (compatible? Maybe include other systems?)
CCA based on Land Cover Classification System approach Dichotomous phase Modular-Hierarchical phase Climate variables (thresholds) Indicators production potential development (phenology) others (NDVI, hotspots...) Specific-technical variables (non-climatic) Accomodates a priori and a posteriori classes
CCA principles Core of CCA: independent of other classifications (e.g. soils, landscape, economics, irrigation potential, inputs) No fuzzy boundaries Year (perennial) and growing season-based (annual) re-definition of variables: nb of rainy days and rain per rainy day rather than Rmonth Low level of “French indices” e.g. Turc's Thermal Factor (Tf = P / (T2 -10 T +200)) orThornthwaite' s Precipitation Effectiveness Ratio
Why a new CCA? New uses of CCA, for instance in climate change studies New data grids, data processing and classification techniques are available A generic Agricultural Climate Classification System (ACCS) can be developed that incorporates other systems and all necessary tools (PCA, NHC) Double entry: find locations based on climate (as defined in ACCS; iso-climates), or determine which climatic conditions are associated with e.g. blue cabbage wasp
Thank you! Source of farmers: 1634 etching by Rembrandt (Het Rembrandthuis Museum, Amsterdam)