Compilation of Q & A format of the book Science and Technology for Civil Services Examinations, Tata McGraw Hill Publication
Chapter 34 Meteorological Science
1 . Weather forecasting is not an exact science. It’s primarily based on observation. But attempts are being made to make it as scientific as possible. Comment 50 words page 482
It is prediction of weather through application of the principles of Physics and gathering of meteorological statistical data. It is difficult to gather this data and this data keeps changing with changes in atmospheric conditions. The best of predictions may be vaid for two or three days after which predictions have to be revalidated.
2. What is synoptic meteorology? 483
It characterises the weather over a large region at exactly the same time in order to organise information about prevailing conditions. Synchronised observations for a specific time are plotted on a map for a broad area from which a general view of the weather in that region is gained.
3 . Describe the techniques adopted to gather meteorological data 100 words 484
Technological advance since the 1960s have led to a growing reliance on remote sensing, particularly the gathering of data with specially instrumented weather satellites as well as observations from ships, aircrafts, radiosondes and Doppler radar. This information is sent to meteorological centres where the data are collected, analysed and made into a variety of maps and charts.
To predict the weather by numerical means, atmospheric models have been developed by using mathematical equations to describe how atmospheric pressure, temperature and moisture will change over time. The equations are programmed into a computer which determines how different variables will change with time.
4. What is the window of meteorological deduction? 484
Weather forecasts made for 12 and 24 hours are typically quite accurate. Forecasts made for two to three days are good. Beyond about 5 days, the forecast accuracy falls off sharply.
5 . Describe the practical applications of weather forecasting. 100 words 484
Agriculture is a major area for use of weather forecasting. Planting and harvesting can be planned better if weather patterns are estimated. It is important in India due to the dependence of the agricultural sector on the monsoon. It has also become important for aviation and sea transport.
Many ocean going vessels as well as military ships use optimum ship routing forecasts to plan their routes in order to minimise lost time, potential damage and fuel consumption in heavy seas. Airlines carefully consider atmospheric conditions when planning long flights so as to avoid the strongest head winds and ride with the strongest tail winds.
Marketing stores require weather forecasts to help with the timing of sales and products ranging from snow tyres to summer clothes. International trading of foodstuffs such as sugar, wheat, corn and coffee can also be severely affected.
6 . How many regional centers of Meteorological observation are there 485
There are 6 at New Delhi, Mumbai, Kolkata, Chennai, Nagpur and Guwahati.
7 . What s the significance of INSAT? 485
India was the first developing country in the world to have its own geo-stationary satellite, INSAT, for continuous weather monitoring of this part of the globe and particularly for cyclone warning.
8 . Describe the major achievements of the (IMD) Indian Meterological Department. 100 words. /486
It has Doppler weather radars installed for more accurate weather forecasting; installation of 100 Digital Cyclone Warning Dissemination systems along the Andhra coast; a Mountain Meteorology Centre was established at Delhi for prediction of avalanches, flash floods and landslides; a new long range prediction model that gives July rainfall for helping Kharif crop sowing; lowering of detection and response times by upgrading the seismic monitoring system.
An Earthquake Risk Evaluation Centre was established at Delhi for seismic micronization. There are also customised forecasts for various other important applications like power distribution, water resources, defence, emergency response and adventure sports.
9 . What are the Agro Advisory services rendered by the IMD 486
It has developed a new long range prediction model that gives more lead time as well as July rainfall as an additional forecast for helping Kharif crop sowing.
10 . What s NCMRWF? Describe it’s vision 50 words 486
The NCMRWF (National Centre for Medium Range Weather Forecasting) was established as the premier institution in India to provide medium range weather forecasts and to render agro advisory services to farmers.
its vision is to become the preferred choice for NWP (Numerical Weather Prediction) guidance over the Indian monsoon region , to develop an earth weather modelling and assimilation system, especially for the monsoon system, to develop newer applications and reach out to society at large, and constantly striving to improve accuracy and consistency.
11 . What is global modeling? 487
NCMRWF runs 2 global spectral models (T-80, T-170) which produce daily global forecasts. The horizontal resolution of these models are 150km and 75km respectively. The atmospheric system they attempt to predict is chaotic. An ensemble prediction system, which involves generation of multiple forecasts as a function of the uncertainty has been developed.
12 . What is Mesoscale modelling? 487
They are essential for accurate prediction of high impact weather such as severe thunder storms, mountain weather forecasts, cloudbursts and cyclones. The mesoscale models (MM5 & ETA) are run up to 72 hours on real-time for high impact weather prediction using initial and boundary conditions from the global forecast model.
13 . What are extended range forecasts? 50 words 488
Currently, the dynamic approach is used for extended range (monthly) prediction based on simulations from the global atmospheric model. Probability of occurrence of excess, normal or deficient rainfall for 6 homogenous regions of the country is calculated.
A more accurate couples system is being developed to understand and predict the monsoon environment a season in advance. Experiments are being conducted to reduce model systematic errors and uncertainties.
14 . What are Ocean State forecasts? 488
They are in great demand for ship routing, fisheries, tourism, oil exploration and port and naval operations. Ocean surface parameters form global and mesoscale models derive most of the ocean and wave models in the country in both real time and research mode. NCMRWF runs a daily global ocean wave model to predict significant wave heights, peak wave direction and wave period.
15 . What are the goals of NCMRW?
It hopes to develop crop model based application tools for agro-advisories, use of remote sensing products to address variability within the agro-climatic zones, and precision farming using GIS.
16 . What s cloud seeding?
It involves seeding clouds with tiny particles to bring more precipitation from them. There two ways to seed clouds. The first uses the coalescence process of rain formation. Small water drops are injected into the base of a cloud, which grow in size by collision with other particles until they are heavy enough to fall down.
The second method employs the ice crystal process of rain formation where small particle of silver iodide are injected into a cloud. These particles act as ice crystals. Water vapour from the surrounding liquid droplets evaporates and freezes onto the iodide particles, which grow larger. The growing crystals eventually become heavy enough to fall as precipitation.