PAKISTAN WINTER RAINFALL PREDICTION Hazrat Mir Cief Met Pakistan Meteorological Department 14 th, October2015
Monsoon 2013 seasonal forecast, PMD, Islamabad, 7 June, 2013 2
Monsoon 2013 seasonal forecast, PMD, Islamabad, 7 June, 2013 3
PMD: Pakistan Meteorological Department Specialized Early Warning Centers of PMD National Weather Forecasting Centre Islamabad (NWFC) Marine Meteorology & Tropical Cyclone Early Warning Centre Karachi (TCWC) National Drought Monitoring Centre Islamabad (NDMC) National Seismic Monitoring & Tsunami Early Warning Centre Karachi (NTWC) Flood Forecasting Division Lahore (FFD) Flood Forecasting & Warning Centre For Lai Nullah Basin Islamabad
Winter Rainfall In the winter season rainfall in Pakistan is caused by Sub-tropical low pressure systems that originate in the Mediterranean Sea, called the Western Disturbances. The country s biggest river Indus is fed by this accumulated snow which plays the major role for agriculture, water reservoirs, glacier basins, power generation, wild-life and ecosystems. Winter precipitation is of tremendous importance from the point of view of water reservoirs which are crucial for country s agriculture and power generation 5
Spatial Distribution of Winter Rainfall Higher rainfall over northern parts. Rainfall intensity decreases towards extreme northern and southern parts. 6
Monthly Spatial Distribution of Winter Rainfall JANUARY FEBRUARY MARCH 7
Monthly Rainfall Variation January to March rainfall are almost similar and contribute 6% to 10% of annual rainfall. 8
Seasons Contribution of Rainfall The contribution of winter (January- March) rainfall is 25 % of annual rain. 9
The Predicting Regression Equation 10
Geographical Locations of the Predictors used in Model 11
Details of Predictors SN Predictor Region/Station Period 1 South American Pressure 2 South American Pressure Mean Station Level pressure Mean Station Level pressure 3 Western rainfall Buenos Aires Cordoba Santiago Buenos Aires Cordoba Santiago Tehran Isphahan Mashad Baghdad November November November December December December December December December December 12
The calculated percentage departure of the expected rainfall in Pakistan from the normal rainfall is classified as follows: Sr. No. Predefined classification of Rainfall Percentage departure of forecast rainfall from normal Classification used for describing the rainfall forecast 1 Above 50 % Largely above normal 2 26 % to 50 % Moderately above normal 3 11 % to 25 % Slightly above normal 4-10 % to +10 % Normal 5-11 % to -25 % Slightly below normal 6-26 % to -50 % Moderately below normal 7 Below -50 % Largely below normal 13
PMD Seasonal Climate Outlook (Oct - Dec) 2015
Seasonal Prediction Approach Goal of Seasonal Prediction is to reduce the adverse socio-economic consequences of climate variability and change. The current scientific approach Lower-boundary forcing, which gives rise to atmospheric perturbations, evolves more slowly than the atmospheric perturbations themselves and that the response of the atmosphere to this forcing is detectable. All the seasonal prediction systems are working on this principal 10/20/2015 15
Seasonal Prediction Method Observed large scale climate Transfer function (Dynamical/statistical model) Predicted large scale climate Observed small scale climate Predicted small scale climate 10/20/2015 16
Observed Area-weighted Rainfall Anomaly for Winter (JFM) Over Pakistan No significant relation with El Niño Source: Pakistan Meteorological Department 10/20/2015 17
Seasonal (Octo-Dec) climate out look 2015. prediction provides information that how the weather condition is expected as compared to the normal atmospheric conditions. Output of the Combined General Circulation Model (CGCM) is downscaled to obtain the seasonal forecast. Normal to above normal (1981-2010) precipitation is expected in most parts of the country during the season October-December 2015. 18
Seasonal (Octo-Dec) climate out look 2015. Con) Khyber Pakhtoonkhwa, Azad Jammu and Kashmir, Punjab and Baluchistan are expected to get above normal precipitation with maximum bias in stations like Muree, Muzafarabad, Saidu Sharif and the adjoining areas. While southern parts of Sindh province are expected to get slightly below normal rainfall durind the season 19
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Monsoon 2013 seasonal forecast, PMD, Islamabad, 7 June, 2013 21
Seasonal Climate Outlook 2015 10/20/2015 22
Monthly Climate Outlook 2015 10/20/2015 23
Monthly Climate Outlook 2015 10/20/2015 24
Monthly Climate Outlook 2015 10/20/2015 25
% Accuracy Level Accuracy Level for Seasonal Forecast by PMD 100 90 80 70 60 50 40 30 41 55 9291 85 86 82 87 88 84 76 78 71 65 75 79 74 62 64 62 51 43 48 42 40 72 40 63 79 83 73 68 45 40 99 91 91 88 78 75 92 75 85 97 94 63 46 20 10 0 10/20/2015 26
Significant Trend of annual Precipitation(mm) across Pakistan (1951-2014) Maximum Increase in Precipitation at Mianwali = 6.18 mm/year Maximum decrease in Precipitation at Ghari Dupatta = 9.15 mm/year
SIGNIFICANT TREND OF MEAN MONTHLY MAXIMUM TEMPERATURE ( C) ACROSS PAKISTAN(1951-2014) Maximum Increase in Max. Temp. at Dalbandin = 0.043 C/year Maximum decrease in Max. Temp. at Cherat = -0.035 C/year
Monsoon 2013 seasonal forecast, PMD, Islamabad, 7 June, 2013 29
Monsoon 2013 seasonal forecast, PMD, Islamabad, 7 June, 2013 30
THANK YOU 31