Sumiya Vandandorj; Erdenebadrakh Munkhjargal; Bazartseren Boldgiv; Batdelger Gantsetseg
Environ Earth Sci
Type and duration of ratin events
Precipitation patterns Mongolia Convective rain Stratiform rain Number and duration of rain events
In addition to the total amount of precipitation, the number, type and duration of rain events play a critical role in hydrological cycle, land surface processes,vegetation and land cover dynamics in such semi-arid regions as Mongoliawherewateravailabilityisthemaindeterminantof ecosystemfunctioningandservices.However,onlyalimited number of studies have so far focused on certain aspects of changes in rain types and durations for Mongolia as a whole, while a relatively large number of studies have examined trends observed in total annual precipitation for the country.In the present study, we evaluated changes in not only the amount, but also in the number and total duration of rain types using the data on start-to-end times of all rain events from 55 meteorological stations scattered throughout Mongolia between 1981 and 2014, a period for which this type of analysis was made possible for the ﬁrst time. Our study conﬁrms that there has been no signiﬁcant change in the amount of mean summer precipitation for almost all parts of the country for the last 34 years, with only a few stations showingasigniﬁcantdecreasingtrend.Intermsofraintypes, the number and duration of convective rains have increased, while those of stratiform rain events have decreased over Mongolia, a trend that is more pronounced around Khangai mountain area in central Mongolia and south-eastern desert steppe and eastern steppe, suggesting a possible transition fromstratiformrainstoconvectiverains.Theﬁndingsofthis research imply that increasing temperature and altered rain type ratios may affect each other as the decreasing number anddurationofstratiformraineventsallowforprogressively longer sunshine period, possibly feeding back to the increasedtemperature.Thereleaseofthislatentheatfuelling the upward movement of moisture and producing the convective rains could be one of the reasons of the signiﬁcant rise in convective rain frequency for the study period. The observed changes in rain patterns have signiﬁcant implications in ecosystem functioning and resource management.