What is SPI drought?
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.
How is the standard precipitation index calculated?
To calculate the SPI (Standard Precipitation Index), a long-term precipitation record at the desired station is first fitted to a probability distribution (e.g. gamma distribution), which is then transformed into a normal distribution so that the mean SPI is zero (McKee et al., 1993, 1995).
What is SPI climate?
The Standardized Precipitation Index (SPI) is a widely used index to characterize meteorological drought on a range of timescales. Concerns have been raised about the utility of the SPI as a measure of changes in drought associated with climate change, as it does not deal with changes in evapotranspiration.
What is SPI project management?
The schedule performance index (SPI) is a measure of the conformance of actual progress (earned value) to the planned progress: SPI = EV / PV. When CPI or SPI are greater than 1.0, this indicates better-than-planned project performance, while CPI or SPI less than 1.0 indicates poorer-than-planned project performance.
How is SPI drought calculated?
The SPI calculation for any location is based on the long-term precipitation record for a desired period. This long-term record is fitted to a probability distribution, which is then transformed into a normal distribution so that the mean SPI for the location and desired period is zero (Edwards and McKee, 1997).
What does rainfall index mean?
Rainfall Index (RI) is based on weather data collected and maintained by the National Oceanic and Atmospheric Administration’s Climate Prediction Center. The index reflects how much precipitation is received relative to the long-term average for a specified area and timeframe.
What does SPI stand for in electronics?
SPI stands for Serial Peripheral Interface—it’s a de facto synchronous communication bus standard. Developed by Motorola in the 1980s, SPI boasts both simple implementation and high-speed data transfer capability.
What is the difference between SPI and CPI?
CPI is the measurement of deviation from the estimated cost of the project. SPI is the deviation from the scheduled time for project. If CPI is less than 1 then project is over budget. If SPI is less than 1 then project is behind schedule.
