Assessment of precipitation excess/deficit in Cotnari and the surrounding area using the Standardized Rain Index

Abstract

The study quantifies rainfall variability, variance, trends, through the Standardized Precipitation Index (SPI) and the de Martonne Aridity Index (DMai), in Cotnari and its surroundings over the last 60 years. The current climate context makes water resources difficult to manage, not to mention the fact that the territory is under the influence of a continental climate, being situated at the western limit of the area with a negative water balance. The study is based on climate data from measurements taken from 1961 to 2020 and had as its main objective the identification of the evolutionary limits of the SPI, the frequency classes of this index for different accumulation intervals (from one month to 12 months), validation of the representative ranges of the SPI using DMai, and, in the end, with the outline of the trends that this index has had and will have in the future. According to the SPI values at the Cotnari Meteorological Station, between 68.4% (SPI 1) and 99.7 % (SPI 12) of the analyzed months, there was recorded a normal amount of rainfall. Between 16.2 % (SPI 1) and 2.0 % (SPI 12) of the months, there was a surplus water balance (extremely wet between 4.7 %) and between 14.3 % (SPI 1) and 0.0 % (SPI 12) a deficit water balance (there were no extremely dry months). The evolution trend of SPI at Cotnari from 1961 to 2020 indicates a slight increase in the quantity of precipitation.

Keywords

• spi
• the de martonne aridity index (dmai)
• negative rainfall balance