Applied Research in Geographical Sciences

Applied Research in Geographical Sciences

The Study of the Impact of Temperature and Wind In the Southern Low Pressure Systems

Author
mahboobeh pouratashi
ASMERC
10.29252/jgs.20.57.223
Abstract
This research aims to study the impact of temperature and wind in the southern low-pressure system and its associated precipitation in the southern regions of Iran. As The southern low pressure system moves eastward, it crosses the southern regions of Iran, causing medium and heavy rainfall in these areas. In this study, two southern low-pressure systems that caused heavy rainfall on March 11, 2015 and January 17, 2000 in southern Iran were selected, analyzed and simulated using the numerical Weather Research and Forecasting (WRF) model. Since the wind and temperature fields play a significant role in the southern low-pressure systems, four experiments were performed for investigating the effects of temperature and wind on the intensification and weakening of the southern system. The simulation results showed that the simulation for the increased (decreased) temperature caused the weakened (intensified) the southern low pressure in the studied area. This result showed that the vertical structure of the southern low-pressure and its physical characteristics are similar to the mid-latitudes cyclones, and these systems were different from the thermal low pressures. The results of wind speed changes showed that the increased (decreased) wind speed simulation caused an increase (decrease) in relative vorticity, thus the southern low pressure was intensified (weakened). In both cases, the rainfall was decreased by the increased temperature simulation, and decreased temperature caused an increase in rainfall. It was also seen that the increase in wind speed caused the special humidity advection to be increased and then the rainfall increased. Also the amount of rainfall decreased when conditions did not provide for the advection of specific humidity or the wind speed reduced.
Keywords
heavy rainfall
southern low pressure
WRF model
south and southwest of Iran
southern cyclone
Alpert, P., Neeman, B. U., Shay-el, Y. (1990). Climatological Analysis of Mediterranean Cyclones Using ECMWF Data, Tellus. 42(A). 65-77.
Alpert, P.; Neeman, B. U.; Shay-El., Y., (1990). Intermonth variability of cyclone tracks in the Mediterranean. J Clim., 3: 1474-1478.
Babu, C.A., Samah2, A.A., Varikoden, H. (2011). Rainfall Climatology over Middle East Region and its Variability. International Journal of Water Resources and Arid Environments 1(3): 180-192.
Barth, H. J., Steinkohl, F. (2004). Origin of winter precipitation in the central coastal lowlands of Saudi Arabia. Journal of Arid Environments 57: 101-115.
Bluestein, H.B. (1993). Synoptic-Dynamic meteorology in midlatitudes. Vol. II: Observation and theory of weather systems. Oxford University Press. 594 pp.
Carlson, T.N. (1991). Mid-Latitude Weather System. University Press Cambridge.
Chen, F., Dudhia, J. (2001). Coupling an advanced land surface-hydrology model with the Penn State-NCAR MM5 Modeling System. II: preliminary model validation. Mon. Weather Rev. 129: 587–604.
D. Argueso, J. M. Hidalgo-Munoz, S. R. Gamiz-Fortis, M. J. Esteban-Parra, (2011). Evaluation of WRF Parameterizations for Climate Studies over Southern Spain Using a Multistep Regionalization. American Meteorologacal Society, 24:5633-5650.
Dudhia, J. (1989). Numerical study of convection observed during the winter monsoon experiment using a mesoscale two- dimensional model. J. Atmos. Sci., 46, 3077–3107.
Iacono, M., Delamere, J., Mlawer, E., Shephard, M., Clough, S., Collins,W. (2008). Radiative forcing by long-lived greenhouse gases: calculations with the AER radiative transfer models. J. Geophys. Res. 113, D13103.
Jansa, A., A. Genoves, M.A. Picornell, J. Campins, R. Riosalido and O. Carretero, (2001). Western Mediterranean cyclones and heavy rain. Part 2: Statistical approach. Meteorol. Appl. 8, 43–56.
Kain, J.S. (2004). The Kain-Fritsch convective parameterization: an update. J. Appl. Meteorol., 43, 170–181.
Krichak,S. , O., Breitgand, J., S. (2012). A Conceptual Model for the Identification of Active Red Sea Trough Synoptic Events over the Southeastern Mediterranean. Journal of Applied Meteorology and Climatology, 51: 962-971.
Lionello, P., Giorgi, F. (2007). Winter precipitation and cyclones in the Mediterranean region: future climate scenarios in a regional simulation. Adv. Geosci., 12, 153–158.
Nasrollahi, N., AghaKouchak, A. (2012). Assessing the Impacts of Different WRF Precipitation Physics in Hurricane Simulations. Center for Hydrometeorology and Remote Sensing, University of California, Irvine, Irvine, California
Nieto, R.; Gimeno, L.; Torre, L. de la.; Ribera, P.; Gallego, D.; García‐Herrera, R.; García, J. A.; Nuñez , M.; Redaño, A.; Lorente, J. (2005). Climatological features of cut‐off low systems in the Northern Hemisphere, Journal of Climate, 18, 3805–3103.
Petterssen, S. (1956). Motion and Motion Systems. Weather Analysis and Forecasting. McGraw-Hill; Vol. I., 428 pp.
Romem, M., B. Ziv, Saaroni, H. (2007). Scenarios in the development of Mediterranean cyclones. Advance Geoscience, 12, 59–65.
Sutcliffe, R. C (1947). A contribution to the problem of development. Quart. J. Roy. Meteor. Soc., 73, 370–383.
Sutcliffe, R. C.; Forsdyke, A. G. (1950). The theory and use of upper air thickness patterns in 1 forecasting. Quart. J. Roy. Meteor. Soc., 76, 189–217.