Drought index calculation method based on saturated water vapor pressure difference

Abstract

The invention discloses a drought index calculation method based on saturated water vapor pressure difference, and the method comprises the steps: defining a standardized saturated water vapor pressure difference index as a drought index, representing the drought condition, and monitoring the drought condition of a land ecosystem; the standardized saturated water vapor pressure difference index calculation method comprises the following steps: acquiring meteorological data of ground temperature, ground air pressure and relative humidity of a meteorological station or a field observation station; calculating saturated water vapor pressure and actual water vapor pressure according to meteorological data; and calculating a standardized saturated water vapor pressure difference index according to the saturated water vapor pressure difference. The new drought index provided by the invention is applied to drought monitoring of agricultural or ecological systems, can reflect drought conditions except atmospheric precipitation supply shortage, is simple in calculation method and accurate and stable in result, and observation data participating in calculation is easy to obtain and does not depend on additional observation instruments, so that the installation and maintenance cost of the additional instruments can be avoided, time and space continuity is achieved, and drought occurring in land ecosystems such as farmlands, forests and grassland can be described more accurately.

Description

technical field [0001] The invention relates to a method for calculating a drought index, in particular to a method for calculating a drought index based on a saturated water vapor pressure difference. It belongs to the application field of satellite remote sensing. Background technique [0002] Drought is a frequent extreme climate event and one of the most destructive natural disasters. Frequent drought disasters will seriously affect the ecological environment, agricultural production, economic activities, and people's livelihood. Existing drought indices for monitoring drought intensity include: Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Soil Moisture Index (SSMI) and Palmer Drought Index (PDSI), etc. However, the existing drought indices generally have limitations, such as (1) the standardized precipitation index (SPI), which can only reflect the drought changes caused by the shortage of atmospheric...

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Problems solved by technology

However, the existing drought indices generally have limitations, such as (1) the standardized precipitation index (SPI), which can only reflect the drought changes caused by the shortage of atmospheric precipitation supply; (2) the standardized precipitation evapotranspiration index (SPEI), which needs to estimate the potential Evapotranspiration (PET), but there are many algorithms for potential evapotranspiration, and different algorithms are very different, resulting in a very large uncertainty in potential evapotranspiration

(3) Standardized Soil Moisture Index (SSMI), which only requires soil moisture observation data, but the current observations are scarce, and the continuity of time and space is poor. In addition, the installation and maintenance costs of observation instruments are high

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