Studying the Moisture Flux over South and Southwest of Iran: A Case Study from December 10 to 13, 1995 Rain Storm

Abstract

During December 10-13, 1995 a destructive flood occurred over the south part of Iran resulting from the intensive rainfall causing the social and economical damages over that area. This study intends to reveal the main moisture source flux which feeds in the rain fall weather system. The precipitation amount over the study area is four times greater than normal mean in December. The relationships between local atmospheric circulation and moisture flux divergence is investigated for this case of rainfall over south of Iran. The data used in these study includes rainfall data, from data processing center of IRIMO (Iran meteorological organization) and reanalysis daily data at every six hours interval for the same period and eight levels of NCEP-NCAR, with resolution 2.5 degrees in 0-80 E and 10-60 N domain. The high pressure circulation over the North East of Arabian peninsula at surface to 700hPa coupled with trough over the East of Mediterranean and west of the Red sea, transfer sufficient moisture in low levels of the troposphere from west of Indian ocean (Oman and Arabian seas), Aden gulf and Red sea to the center and North of Arabia and south of Iran. The average of perceptible water content in all troposphere level (1000-300 hPa) that comes from the above mentioned region to the South West and south of Iran is about (6-8) 10^-3 kg/m²s^-1. The most divergence of moisture flux in the lower level is from the west of the Indian Ocean while the source of moisture in middle and higher levels are from Aden gulf and the Red sea.<br /

Impact of Moisture Flux and Vertical Wind Shear on Forecasting Extreme Rainfall Events in Nigeria

“…The mass convergence term is usually the dominant term, and observations have shown that the moisture advection term can significantly contribute to the development and subsequent intensification of storms. By combining the effects of mass convergence as a low-level forcing mechanism with moisture availability, moisture flux incorporates most of the ingredients necessary for convection (Roshani et al 2012).…”

“…These effects depend not only on the sensitivity of populace to climate change but also on their ability to adapt to risks and changes associated with it. Since the atmospheric moisture budget plays an important role in the hydrology of a particular region, the changing weather patterns caused by climate change has increased the incidences of extreme rainfall events (Roshani et al 2012;Weisman et al 1988). Rainfall variability associated with climate change has impacted socioeconomic activities such as agriculture, food security, water resources management, health sector, hydroelectric power generation, and dam management among others in Nigeria (Bello 2010).…”