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PAKISTAN METEOROLOGICAL DEPARTMENT |
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Research and Development Division |
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Modeling Activities |
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To contact us: |
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Phone: +92-51-9250360-7 Fax: +92-51-9250368 E-mail: pmd@pakmet.com.pk |
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Numerical modeling Numerical modeling is the process of obtaining an objective forecast of the future state of the atmosphere by solving a set of equations that describe the evolution of variables (temperature, wind speed, humidity, pressure) that define the state of the atmosphere. The process begins with analysing the current state of the atmosphere by taking a previous short-range forecast and using observations to amend this forecast so that the best guest of the current true state of the atmosphere is obtained. All numerical models of the atmosphere are based upon a set of governing equations. Numerical models differ in the approximations and assumptions made in the application of these equations, how they are solved and also in the representation of physical processes.
Regional Climate Model Climate models are increasingly used for downscaling climate scenarios, seasonal climate predictions, land use climate impact and ocean-atmospheric interaction studies all over the world. A climate model consists of complex computer program / programs. These programs look at several mathematical equations that govern the atmospheric processes at once. They take into account conservation of mass, energy, momentum in a grid box system (the world is divided in to several grid boxes). The model focuses on each grid box and the transfer of energy between grid boxes. The aim is to reproduce as faithfully as possible the real climate system. Pakistan Meteorological Department (PMD) is using the PRECIS regional climate modeling system of developed by Hadley Centre of Meteorological Service, United Kingdom and RegCM3 (Regional Climate Model version 3) of ICTP, Trieste, Italy, for developing climate scenarios, climate predictions, land use / land cover climate impact and for climate and climate change related research. The models that are functional and installed at Pentium4 Servers at Research & Development (R & D) Division of PMD, Islamabad.
Numerical Weather Forecasting Systems The simulation of atmospheric processes on a computer with the aim of taking their latest state to derive a prognosis of the future development is called numerical weather forecasting. Nowadays most of the weather forecasts are compiled on this basis. Pakistan Meteorological Department (PMD) is using Mesoscale Model version5 (MM5) for numerical weather forecasting and is also preparing to use the High Resolution Model (HRM) with a grid length of 7km in near future. The HRM is developed by DWD (National Meteorological Service of Germany). The models have been installed at Research & Development Division of PMD. The data of Global Model (GME) also of DWD shall be used as initial conditions in HRM for the numerical weather forecasts. The use of this high resolution model will further improve the weather forecasts issued by PMD and also enhance the accuracy of weather predictions. |
