Agricultural drought index and monitoring on national scale. LU Houquan National Meteorological Center, CMA

Transcription

1 Agricultural drought index and monitoring on national scale LU Houquan National Meteorological Center, CMA

2 Contents Agricultural drought disasters in China Agricultural drought indices --Precipitation anomalies --Soil moisture --Remote sensing drought index --Crop Water Deficit Index --Integrated Drought Index Integrated agricultural drought monitoring

3 Part 1: Agricultural drought disasters in China The area of cropland damaged by drought was on the range from 40% to 80%,occupying that caused by weather disasters Data from the National Statistic Bureau)

4 Agricultural drought with seasonal and regional feature in China Due to: Several climate types (uneven distribution of precipitation on spatial and temporal, large variability) Various agriculture styles in different regions (crop varieties, cropping system, water requirement for various crops) Different water supply conditions for agricultural crops

5 Seasonal agricultural drought Spring drought: impacting on winter wheat and other crops sowing in northern China, and impacting on rice transplanting in southern China Early summer drought: impacting on some crops sowing and autumn-matured crops in northern China Midsummer drought: impacting on rice in southern China Autumn drought: impacting on winter wheat sowing in North China Winter drought: impacting on over-winter crops in South China

6 Part 2: Agricultural drought indices The main factors related with agricultural drought Climate (evaportranspiration, precipitation) Soil (type, moisture) Crops (species, stage of development) Irrigation capacity (facilities, water resource)

7 Agricultural drought index --Precipitation anomalies (PA) Pa P P P 100% Pa is percentage of precipitation anomalies(%) is climatic normal of precipitation (mm) of the 30 days P is precipitation of 30 days (mm) Advantage: observable, denoting storage of water for agriculture, especially for rainfed farming Disadvantage: can t reflect water consumption and water demand of crops P

8 Agricultural drought index -- Relative soil moisture (RSM) w Rw 100% f c Rw is relative soil moisture % W is soil moisture on weight percentage % fc is field capacity % Advantages : measurable and simulated, expressing how much available water in soil for crops Disadvantage: with a poor representativeness on spatial, can not be use to paddy field

9 Agricultural drought index --Crop Water Deficit Index (CWDI) CWDI i ET a P ET a I CDWI CWDIi is crop water deficit index of 10 days, ETa is actual evapotranspiration of 10 days, P and I is precipitation and irrigation of 10 days, ai is weight coefficient Advantages: to judge if precipitation and irrigation could meet the water demand of crops or not Disadvantage: unmeasured, can t express other factors influence on water consumption and with many coefficients n i 1 a i CDWI i

10 Crop water requirement ET a = K c ET o ET a = crop water consumption (evapotranspiration) K c = crop coefficient ET o = reference crop evapotranspiration

11 FAO Penmen-Monteith Equation for ET o ET o ( R n 900 G) T 273 (1 0.34U R n = net radiation at crop surface G = soil heat flux T = mean daily air temperature at 2 m height U 2 = wind speed at 2 m height e s -e a = saturation vapour pressure deficit = slope vapour pressure = psychrometric constant 2 U ) 2 ( e s e a )

12 Agricultural drought index --Remote sensing drought indices DRG n i 1 f i w i Integrated by Thermal Inertia method, Crop Water Stress Index,Temperature and Vegetation Drought Index Advantages: observable, continuously on spatial, reflecting status of soil moisture and crops response to water supply Disadvantage: impacted by cloudy and vegetations on ground, data source unstable

13 Agricultural drought index --Integrated Drought Index IDI n i 1 f i DI i For various regions and cloud status, precipitation anomalies, soil moisture, CWDI and remote sensing indices would be given different weighting.

14 Agro-climatic zoning of China LAI Kc CN DI weight

15 Part 3: Integrated agricultural drought monitoring Remote Sensing Precipitation anomalies Crops water deficit Soil moisture Integrated drought index In Soil plant-atmosphere continuum, overall agricultural drought monitoring

16 Soil moisture Soil texture Crop stage Mete. data Crop stage Mete. data NOAA EOS/MODIS FY-1 FY-2C Soil moisture Index Crop water deficit Index Precipitation anomalies Remote Sensing Drought Index Dynamic soil moisture model Dynamic CWDI Drought model Moving preci. anomalies Remote Sensing Drought model Integrated agricultural drought model on region scale Agricultural drought monitoring system on GIS Agricultural drought monitoring operation Flow chart Products of Agricultural drought monitoring

17 Surface agricultural drought monitoring system Remote sensing monitoring system Integrated monitoring system On the GIS, integrated agricultural drought monitoring system

18 Integrated monitoring Case on 1st decade Aug.2006 Remote Sensing Crop water deficit Soil moisture

19 Soil moisture simulation

20 Integrated monitoring Case on 1st decade Jan Remote Sensing Precipitation anomalies Soil moisture Crop water deficit

21 Agricultural drought monitor and prediction on national scale product released by NMC

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