Where is evapotranspiration highest globally?
In the Congo River Basin, there is high potential evapotranspiration and ample precipitation, so less of the potential goes unused. The result is high actual evapotranspiration and a much more humid climate with abundant plant life.
What is the rate of evapotranspiration?
The evapotranspiration rate is normally expressed in millimetres (mm) per unit time. The rate expresses the amount of water lost from a cropped surface in units of water depth. The time unit can be an hour, day, decade, month or even an entire growing period or year.
How do you calculate evapotranspiration rate?
Generally what you’ll do is add the highest temperature during a 24-hour period to the lowest temperature during that same period, then divide that sum by 2. This will give you a good estimate for the average temperature during that time.
Why is evapotranspiration low in the southwestern United States?
Why is Evapotranspiration low in the southwestern United States? Because the soil is not fertile and the dry weather of the southwest results in little to no vegetation. With less vegetation comes significant;y less evapotranspiration.
Why is evapotranspiration higher in summer?
Potential Evapotranspiration PET is higher in the summer, on less cloudy days, and closer to the equator, because of the higher levels of solar radiation that provides the energy for evaporation.
Where does evapotranspiration occur?
Evapotranspiration (ET) is a term used to describe the water consumed by plants over a period of time. Evapotranspiration is the water loss occurring from the processes of evaporation and transpiration. Evaporation occurs when water changes to vapor on either soil or plant surfaces.
What fraction of rainfall is evapotranspiration?
On an annual basis, ET generally involves a large fraction of the total precipitation. In arid climates most of the rainfall, 90% or more, may be lost through ET. In more humid climates, ET may account for 40 to 70% of the annual precipitation.
Why is evapotranspiration high in the southeastern United States?
The Southeastern United States has the highest amounts of evapotranspiration in the country due to the high amounts of both precipitation and incoming solar radiation (U.S. Geological Survey, 1990). This creates a significant sink in the water supply in this area and makes evapotrans piration estimates essential.
Which conditions is favors higher evapotranspiration rate?
Energy availability. The more energy available, the greater the rate of evapotranspiration.
What are the factors that controlled the rate of evapotranspiration?
Factors that affect evapotranspiration include the plant’s growth stage or level of maturity, percentage of soil cover, solar radiation, humidity, temperature, and wind.
How much has global evapotranspiration changed over time?
In Addition, we have assessed evapotranspiration variations over the same time period using an ensemble of process-based land-surface models. Our results suggest that global annual evapotranspiration increased on average by 7.1 ± 1.0 millimeters per year per decade from 1982 to 1997.
How are the maps of potential evapotranspiration calculated?
The maps of potential evapotranspiration (ET) shown below are calculated from satellite-derived measurements of solar radiation and average air temperatures. The ET values on the maps are a reasonable estimate of daily crop water use for most crops that have reached at least 80% coverage of the ground.
Where can I find MODIS evapotranspiration time series data?
MODIS was first launched aboard the Terra satellite in 2000, and the full 11-year evapotranspiration time series is available as 8-day , monthly, and annual averages. A toolbox for downloading monthly MODIS data is available in the ArcGIS Resource Center.
What is mod16 global evapotranspiration?
This project is part of NASA/EOS project to estimate global terrestrial evapotranspiration from earth land surface by using satellite remote sensing data. MOD16 global evapotranspiration product can be used to calculate regional water and energy balance, soil water status; hence, it provides key information for water resource management.