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Why we need a new climate classification for agriculture (CCA) R Gommes, M Bernardi, F Nachtergaele, FAO J. Grieser, DWD/GPCC WORKSHOP ON CLIMATIC ANALYSIS.

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Presentation on theme: "Why we need a new climate classification for agriculture (CCA) R Gommes, M Bernardi, F Nachtergaele, FAO J. Grieser, DWD/GPCC WORKSHOP ON CLIMATIC ANALYSIS."— Presentation transcript:

1 Why we need a new climate classification for agriculture (CCA) 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)

2 Some history... (1) Koeppen ( ) 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 1.5 Thornthwaite (1931): Precip. Effectiveness Ratio PER = 115 * [ inches rain / (Fahrenheit-10)] 10/9 PEI = Sum monthly PER; TEI = Sum TER

3 Some history... (2) Thornthwaite (1948): introduces ET and Moisture Index monthly PE = 1.6 daylength (10 T / HI) a HI = (T / 5) a = HI HI 2 + etc. Budyko (1955) introduces radiation Seljaninov ( ): “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.

4 Non-linearity of response

5 Temporal variability (Zimbabwe rain )

6

7 The climate “complex” (286 Latin-American stations, average March data)

8 Correlations between variables

9

10 Cambodia rainfall 7 classes

11 Tanzania rainfall types

12 URT

13 Burkina Faso

14 Length of growing period

15 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?)

16 LCCS: opening screen

17 CCA based on Land Cover Classification System approach 1.Dichotomous phase 2.Modular-Hierarchical phase 1.Climate variables (thresholds) 2.Indicators 1.production potential 2.development (phenology) 3.others (NDVI, hotspots...) 3.Specific-technical variables (non-climatic) 3.Accomodates a priori and a posteriori classes

18 LCCS:dichotomous phase

19 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 R month Low level of “French indices” e.g. Turc's Thermal Factor ( Tf = P / (T T +200) ) or Thornthwaite' s Precipitation Effectiveness Ratio

20 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

21 Thank you! Source of farmers: 1634 etching by Rembrandt (Het Rembrandthuis Museum, Amsterdam)


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