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Diagnosis of tropospheric moisture over Saudi Arabia and influences of IOD and ENSO

Chakraborty, A and Behera, SK and Mujumdar, M and Ohba, R and Yamagata, T (2006) Diagnosis of tropospheric moisture over Saudi Arabia and influences of IOD and ENSO. Monthly Weather Review, 134 (2). pp. 598-617.

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Abstract

A diagnostic study of atmospheric moisture data over Saudi Arabia derived from a 43-yr National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalysis revealed that moisture convergence in the lower troposphere and divergence in and above the middle troposphere occurs throughout the year. Although the amount of precipitable water content in the middle troposphere is high, precipitation is less than expected over this semiarid region during a boreal summer monsoon season because of strong moisture divergence. The net tropospheric moisture flux over the arid and semiarid regions of Saudi Arabia shows seasonal and interannual variability. The seasonal variability has a strong semiannual signal with its primary peak February-April and its secondary peak June-August. This pattern is consistent with a similar semiannual signal observed in rainfall climatology. The restricted moisture supply to southwestern Saudi Arabia during summer presumably explains the lack of precipitation in other areas of the country. Winter precipitation, however, is widespread. The increased transport of net atmospheric moisture flux is higher during El Niño and positive Indian Ocean dipole (IOD) phenomena. During these events, influx across the Red Sea (west) side of Saudi Arabia increases. The net flux to the region is reduced by a slight increase of outflux across the Persian Gulf (east) side. Reanalysis data and model-sensitivity experiments show that El Niño or a concurrent positive IOD and El Niño event more strongly amplify net transport than does an independent positive IOD event. The partial-lag correlation analysis with net moisture flux from the Red Sea side shows that the positive IOD mode has a peak correlation coefficient of �0.5 with close to a 5-month lead and that El Niño has a peak correlation coefficient of �0.6 with close to a 2-month lead. © 2006 American Meteorological Society.

Item Type: Article
Additional Information: Copyright of this article belongs to American Meteorological Society.
Uncontrolled Keywords: Climate change; Computer simulation; Correlation methods; Moisture; Precipitation (meteorology); Rain; Troposphere, Boreal summer monsoon season; Interannual variability; Rainfall climatology; Tropospheric moisture flux, Climatology, climatology; El Nino-Southern Oscillation; troposphere
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 12 Dec 2014 10:16
Last Modified: 12 Dec 2014 10:16
URI: http://moeseprints.incois.gov.in/id/eprint/1964

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