How do you calculate effective drought index?

How do you calculate effective drought index?

Effective Drought Index (EDI) The summation term is the sum of the reciprocals of all the months in the duration N (i.e. for N=3 months), this term will be equal to 1 1 + 1 2 + 1 3 .

How is Palmer Drought Severity Index calculated?

The PDSI is calculated based on precipitation and temperature data, as well as the local Available Water Content (AWC) of the soil. From the inputs, all the basic terms of the water balance equation can be determined, including evapotranspiration, soil recharge, runoff, and moisture loss from the surface layer.

What is effective drought index?

Effective drought index (EDI) is a method, which is based on the cumulative daily precipitation by weighting method. This method is the only known way that determines daily dry and drought periods that last for several years. In Iran, few studies were conducted on drought using the EDI index.

How do you calculate drought intensity?

3.1. SPI is recommended by the WMO as a standard drought monitoring index [20] and is calculated by taking the difference of the precipitation, Xi from the mean, ˉX for a particular time step, and then dividing it by the standard deviation, σ [21].

What is SPI drought?

The Standard Precipitation Index (SPI) is a relatively new drought index based only on precipitation. It’s an index based on the probability of precipitation for any time scale. Some processes are rapidly affected by atmospheric behavior, such as dry land agriculture, and the relevant time scale is a month or two.

Which is the most commonly used drought index?

While the PDSI is the oldest and most well known, the SPI is the most widely used index for understanding the magnitude and duration of drought events.

What is drought duration?

Occurrence of drought is a slow process lasted for a long time until the rainy season come. This natural disaster has broad and severe impact. SPEI is drought index used for quantifying drought occurrence, and can be used to analyze duration, severity and intensity.

How do you survive a drought?

1. Plant native and/or drought-tolerant grasses, ground covers, shrubs and trees. They don’t need water as frequently and usually will survive a dry period without watering.
2. Install water efficient irrigation devices, such as micro and drip irrigation and soaker hoses.
3. Use mulch to retain moisture in the soil.

What does SPI tell a geographer?

The SPI specifically addresses the intensity of meteorological drought, or precipitation deficit. However, interpreting the magnitude of the precipitation deficit can be challenging, because precipitation climatology varies widely over geographical regions as well as temporal scales.

What are the types of drought?

Types of Drought

• Meteorological Drought. When dry weather patterns dominate an area.
• Hydrological Drought. When low water supply becomes evident in the water system.
• Agricultural Drought. When crops become affected by drought.
• Socioeconomic Drought.
• Ecological Drought.

How do we classify droughts?

To help with drought classification and monitoring, scientists have defined several types of drought:

1. Meteorological Drought. When dry weather patterns dominate an area.
2. Hydrological Drought. When low water supply becomes evident in the water system.
3. Agricultural Drought.
4. Socioeconomic Drought.
5. Ecological Drought.

What breaks a drought?

The end of a drought can occur as gradually as it began. A single soaking rain will provide lasting relief from drought conditions, but multiple such rains over several months may be required to break a drought and return conditions to within the normal range.