 ... ... ... ... ... ... ... ... this is very very important for this central point only we have discussed something earlier to understand this topic very well so considering this today we like to discuss on types of weather forecast and details it is very very important having understood properly on crop production and risk weather sensitive crops weather sensitive stages weather sensitive your form operations and crop weather interaction it is now we have come to discuss on the types of weather forecast and their details now let me say what is weather forecast this must be understood properly so forecasting may be defined in different way forecasting is a general word forecasting your astrology forecasting something so forecasting weather is something different from other things so forecasting future weather change in spatial is very very important and also temporal spatial means different locations and temporal means within between months and other things so two dimensions are there by employing different scientific tools this is very very important so forecasting future weather change in spatial and temporal dimension by employing different scientific tools is very very important it can be also defined as predicting future weather change in spatial and temporal dimension I have changed here future weather change in spatial and I have used new weight against forecasting used predicting again I like to define in a third way foretelling so the only forecasting predicting foretelling or differing from the same statement others are very very similar so weather forecasting is nothing but pre telling or foretelling or predicting or informing the people of the anticipated weather events to be expected now let us move to somewhere the scales of meteorological motion this is very very important unless you understand the meteorological scale it is very difficult to develop weather forecast or to interpret weather forecast or something else so one is planetary scale the word itself indicates that it covers the entire the part of different countries see this horizontal scale is 2000 to 5000 kilometer only more than that so India India is being covered under horizontal scale and vertical scale is 10 kilometer so you are covering India troposphere that we were discussing so the first week troposphere see from the polar it is 8 kilometer from the equator it is 10 to 11 kilometer so it goes up to 10 kilometers then time scale 200 to 400 hours this weather system once develops the scale develops the weather system stays for 200 to 400 hours it can be divided by 24 hours to make days so this is the planetary scale okay then coming to the synaptic scale this is some other scale the horizontal distance is a 502,000 kilometers may be a state or two or three states southern India east India western India so by doing this scale only the Indian southwest monsoon being predicted in under long range forecast east India what would be the rain west India what would be rain south India what would be rain and north India what would be rain and the vertical scale also you are covering complete in their troposphere and the time scale is 100 hours now coming to the meso scale climate this is between the micro and your macro climate these both planetary and synaptic scales are macro climate then meso climate this is a 1 to 100 kilometer horizontal may be a district or a part of district then vertical is 1 to 10 kilometer and the time scale is 1 to 16 hours coming to the micro level if you talk about micro level there must be also the extreme micro level also is this is less than 100 meter not a kilometer meter it is only 200 meter small scale and not hours is 16 to 12 minutes so this is a scale being used to develop a weather forecast in metallurgy and also it is being applied in agriculture also so moving to the next slide methods of weather forecasting how weather forecast is being given what are the mother say the institution they adopt synaptic method we were seeing synaptic scale now under the same scale we use a synaptic method the characters using weather elements observations at surface level surface observatories and upper level made from different locations okay weather chart is prepared to indicate present status of atmosphere that is your weather weather is day to day change in the atmosphere so by using surface observatory observations upper level observations of different locations a weather chart is prepared indicating the present status of the atmosphere then present weather what was happening in the earlier week were also studied plus the information is satellite is also being put together and also we examine analog years analogies when this type of weather occurred in the past so what was the impact how the weather system moved so based on all those things they develop weather forecast for coming 5 days or 6 days or 7 days according to the type of the forecast this is a good method this is still being adopted in India and the second method is statistical method in the case of the statistical method multiple regression arima model arithmetic regression integrated moving average this method is being used especially for developing long range weather forecast that we will be discussing in the next slides the third one is advance method numerical weather prediction the atmosphere is divided into so many profiles and each profile you measure the temperature humidity wind speed and all those atmospheric vapor pressure everything then you put under matrix of different layers then you produce equations so equation drawn from coriolis force frictional force pressure gradient from force and gravitational force are integrated in the multiple equation and it becomes a model very cumbersome and a precise model model is run from the present to future so initial condition is very very important this is very very important model is run from present to future what is happening now and what will happen in future then for that you have to put the initial condition initial unless you put the initial condition what is happening today it is impossible to go for the future well I like to say in our home example without any foundation you cannot build in a castle or any building so initial condition is very very important these are the methods being used to develop weather forecast now after studying the meteorological scale and the methodology to be used now what are the types of forecast that exist in the world especially in India one is now cost now cost now itself say that what now instant forecast so it is a short time weather forecast very very short time forecast for next hours what will happen earlier when we were discussing about the precipitation I was saying that your hail storm so hail storm cannot be predicted in advance of a one new days or two days it is very very difficult it can be predicted another in advance so for predicting the hail storm this now cost is very useful so this is to warn the public so now cost is very very important but not important to agriculture for public safety this is very very important then the second type of forecast is short range forecast short a short time weather forecast issued for 24 hours what will happen tomorrow this is based on the model and based on the experience of the forecaster what will happen the next day so 24 plus 24 this is being given for 48 hours or two days that is short range forecast then the third forecast is medium range forecast medium so three to ten days or three to seven days like that so medium range forecast a weather forecast issued for a period extend from three days to seven days so how forecast goes one hour two days and three to seven days then long range forecast long range I was saying about a east India forecast when I was discussing about a synaptic and miso scale forecast I was mentioning about in the long range forecast for southeast monsoon season rainfall so here more than seven days that's all but it may go up to a season 90 days okay then the the last type of forecast is seasonal climate forecast though it is not a differing from your long range forecast in the case of the long range forecast I told in the methodology used is Arima model statistical model in the case of the seasonal climate forecast this terminology was pronounced by australian scientist and in Tamil Nadu this type of information means being developed by employing a software rainman software this we got it from our australian government and this is being used for seasonal climate forecast you must understand the difference between though these two forecast gives the forecast for anticipated rainfall only up to a season of 90 days they differ very much in the case of the long range forecast you give forecast only for part of India and whole of the season part of India suppose east and india what would be the rainfall we never bothered about the state we never bothered about the district we never bothered about it all similarly we never bothered about the months of rainfall to be received we bother about only seasonal rainfall but in the case of seasonal climate forecast both you can have spatial dimension as well as a temporal dimensions you can able to predict to forecast rainfall for a particular village for different months of the season suppose a south east mounds and forecast is given in the seasonal climate forecast means it can be given for June, July, August and September but such a thing is not available in the long range weather forecast then coming to the other part of the details of the different weather forecast you could see very interestingly and the slides now costing that we have discussed under types of forecast this is given by india meteorological department india meteorological department so the forecast the weather elements are your thunderstorm dust storm cold and heat waves these cold and heat waves we ever discussed already in the part of our lessons so this is the weather elements to be forecasted and now costing methods used synaptic as well as weather made so both are very very important then lead time 1 to 2 hours earlier of the events 2 hours earlier of the events and the accuracy is 92 98% if I say the hail storm is to come by 11 30 or 12 30 by 10 o'clock means definitely at 90% probability the things will happen in a particular area then coming to the short range forecast this is also again given by india meteorological department here the forecast covers what would be the cloud cover in the coming days and its rainfall quantity temperature and the cyclone warning also this short range is being used and the meteorology is synaptic and weather may and numerical weather prediction model that is advanced model and this stays for 1 day plus 1 day 80 to 90% then media range weather forecast this is again given by IMD earlier it was given by national center for media range weather forecast that institution has been amalgated with IMD now so IMD takes the responsibility presently for issuing the medium range weather forecast here rainfall temperature relative humidity wind speed wind direction and the cloud cover or covered which are foremost important for taking form decision especially for the crop management to reduce the risk then here they use two methods global numerical weather prediction model it is nothing but same numerical weather prediction model but something precise and also regional climatic model so these two models are being used this is three to ten days and accuracy is 72 75 days now coming to the other forecast media range there are two things one is issued by the IMD another one is by Tamil Nadu agriculture university here same weather parameters being covered but we use a regional climate model here the TNIU uses a regional climate model that I have pointed out in the earlier slide also this model being also so advance lee being given 70s earlier and accuracy is 72 70% then long range forecast that we have discussed already IMD seasonal rainfall statistical regression like ARIMA model arithmetic regression integrated moving average model 32 40 days in advance of the events to be occurred and accuracy is 60% now seasonal climate forecast again TNIU seasonal rainfall here rainmen software from australia then 52 20 days earlier 60% one interesting thing is when you start from now costing in the accuracy is 90 to 90% short range 80% media range is 70 to 70% then finally seasonal climate forecast 60 long range so when you forecast for more than seven days your accuracy gets reduced that is the information to be derived from this discussion now continuing the same thing who are the clients how these type of weather forecast is being communicated to the farmers such information we could see presently so now costing the clients are public only public so radio and television and dailies are being used to communicate the message develop usefulness for agro-adversary it cannot be used for developing any agro-adversary because the event is going to occur within an hour from the time now so we can't prepare anything anything so if we can't prepare any agro-adversary then resolution state level so resolution means a coverage point suppose a 5 x 5 meter 30 x 30 meter grade point level so here it is a state level so not for in a district level state level short range public including farmer farmers also can use this radio television and dailies and agro-adversary development it is impossible because it is being given one day plus another one day two days only so we can't prepare any advisory even it is prepared it cannot be communicated to the farmers for taking action it is again are given to state level level then media range forecast mainly for farmers only just to reduce the crop production risk so our ex-honorable prime minister Rajiv Gandhi and our Indira Gandhi after seeing all the struggles of the farmers they have developed this medium range of weather forecast under a new deal game and started functioning from I hope from 1991 onwards so what they do is here very interesting that we will be seeing at a later times the forecast is developed at the district level not the state level district level and they critically analyze what is the cross standing crop how the crop is there is there any pest and disease and based on the crop weather interaction other that is based on your weather forecast what will happen to the crops requirement or crops impact then they prepare agro-adversary and communicated to the selected farmers or farmers they give their mobile number to the concerned organization the message is being given to those farmers highly useful since there is a lead time of more than three days to take form decisions suppose if I say today is say first day so with something will happen in fourth day if I communicate by today itself you can prepare yourself for the constant date so this forecast is very very useful to the farming community then media range forecast again farmers website highly useful this is for block level this media range of further forecast is given by our Tamil Nadu agricultural university in India they use a regional climate model and see state level state level not useful not useful district level 80% useful this is block level highly useful to the farmers because it covers only 50 to 60 villages then long range forecast again highly useful for farmers television tailies and radio moderately use for developing our agro-adversary north south east and west India that is the area they give it then another seasonal climate forecast given by for TNAU to farmers so television delies is state department of agriculture website and TNAU research station highly useful for preparing agro-adversaries and it is given at a district level so these are the some things we have land on the types of weather forecast and some more things are available in the next class that will be discussed so we have seen today the what is weather forecast and what is the meteorological scale to be used what are the methodology being used to develop a weather forecast and also different types of weather forecast how they are useful to the farmers that we have seen but one thing you are not going to develop any weather forecast because the weather forecast development is such a wonderful advanced technology you need a very quick and big computers that we do not have so please understand what is weather forecast how is this weather forecast you to be used for developing agro-adversary is very very important that will be studying in next class thank you very much