LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...

Page created by Max Swanson
 
CONTINUE READING
LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...
Earth System Science Organization (ESSO)
        Ministry of Earth Sciences (MoES)
         India Meteorological Department

                   Presents

  LONG RANGE FORECAST UPDATE
              FOR
2014 SOUTHWEST MONSOON RAINFALL
                   9th June, 2014
LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...
Currently used 2-Stage Forecast System for
  All India (Nation-wide) Season Rainfall

                                             1st Stage
                                             Forecast based
                   All India                 on 5 predictors
               June – September      April   requiring data
                    Rainfall                 up to March

              Update for All India           2nd Stage
 June         June – September               Forecast based
                   Rainfall
                                     June    on 6 predictors
                                             requiring data
                                             up to May

                                                    13-Jun-14
LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...
ESSO-IMD’s Operational long range Forecast for the 2014
  Southwest monsoon rainfall over country as a whole
 (a) Quantitatively, the monsoon seasonal rainfall is likely to be
 95% of the Long Period Average (LPA) with a model error of ± 5%.
 The LPA of the season rainfall over the country as a whole for the
 period 1951-2000 is 89 cm.
 (b) The 5 category probability forecasts for the Seasonal (June to
 September) rainfall over the country as a whole is given below:

                                         Forecast     Climatological
                       Rainfall Range
         Category                       Probability     Probability
                         (% of LPA)
                                           (%)             (%)
         Deficient          < 90            23              16
       Below Normal       90 - 96           33              17
          Normal         96 -104            35              33
       Above Normal      104 -110           8               16
           Excess          > 110            1               17

                                                                 13-Jun-14
LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...
Monsoon So Far ….
                               IMD had forecasted that the
Advancement of Monsoon 2014     monsoon will set over Kerala on 5th
                                June with a model error of ±4 days.

                               Southwest monsoon set over
                                Andaman Sea on 18th may 2 days
                                earlier than normal date.

                               Set over Kerala on 6th June 2014,
                                which is 5 days later than its normal
                                date

                               As on 9th June 2013, The northern
                                limit of monsoon continue to pass
                                through 12.0°N/60.0°E,
                                12.0°N/70.0°E, 12.0°N/74.0°E,
                                Kozhikode, Coimbatore, Cuddalore,
                                13.0°N/83.0°E, 16.0°N/87.0°E,
                                18.0°N/90.0°E and 21.0°N/92.0°E.

                                                                4
 29th June, 2010
LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...
Second Stage Forecasts to be issued….
                                                  Quantitative and probabilistic
                   All India                      forecasts have been prepared

                                            Update for All India
                                         June – September Rainfall

                                             All India Monthly
                                          (July & August) Rainfall

              4 Geographical Regions

                                       June – September Rainfall for
                                        Four Geographical Regions

                                                                             5
13-Jun-14
LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...
Second Stage Forecasts: Method

a)    Forecast update for the southwest monsoon
      season (June-September) rainfall over the country
      as a whole using a 6-parameter ensemble
      statistical model with a model error of ± 4%.

b)    Forecast for the monthly rainfall over the country
      as a whole for the months of July & August using
      separate principle component regression models
      with a model error of ± 9%.

c)    Forecasts for the southwest monsoon season
      (June-September) rainfall for the following four
      broad geographical regions of India using separate
      principle component regression models with a
      model error of ± 8%.
                                                      6
29th June, 2010
LONG RANGE FORECAST UPDATE FOR - 2014 SOUTHWEST MONSOON RAINFALL EARTH SYSTEM SCIENCE ORGANIZATION (ESSO) MINISTRY OF EARTH SCIENCES (MOES) INDIA ...
Predictors used for Update Forecast for the
      Seasonal Rainfall over the Country as a Whole: 2014

Geographical Location
of the 6 Predictors

          SN                       PARAMETER                           Period
          1    NE Pacific to NW Atlantic SST Anomaly Gradient         DEC+JAN
          2    Equatorial SE India Ocean SST                            FEB
          3    East Asia MSLP                                        FEB + MAR
          4    NINO 3.4 SST Anom. Tendency                         MAM(O)-DJF(-1)
          5    North Atlantic MSLP                                     (MAY)
          6    North Central Pacific Zonal Wind Gradient 850 hPa       (MAY)
                                                                                13-Jun-14
Statistical Ensemble Forecasting System for
 Seasonal Rainfall over Country as a whole: June

  The average of the ensemble forecasts from best out of all
possible MR (multiple regression) and PPR (projection pursuit
         regression) models gives the final forecast.

                                                                8
Performance of the
June Ensemble Forecasting System: 1981-2013

        RMSE = 6 % of LPA

                                          13-Jun-14
Probabilistic Forecast Based on
    6- Parameter Ensemble Forecasting system:
Predefined Rainfall Categories for Country as a whole

                           Rainfall Range
              Category       (% of LPA)

              Deficient         < 90

            Below Normal       90-96

              Normal           96-104

            Above Normal      104-110

              Excess           > 110

13-Jun-14
Tercile categories for Probability Forecasts of
       Monthly Rainfall over the Country as a Whole

               Tercile Break Points
                     µ ± 0.43 σ
                                                    July       August
                                                   Model        Model
                                      Category    Rainfall     Rainfall
                                                   Range        Range
                                                 (% of LPA)   (% of LPA)
                                      Below
                                                    106
 All the 3 categories have           Normal
  equal climatological
  probability (33.33% each)

                                                                         11
Tercile categories for Probability Forecasts of
Season Rainfall over the 4 Geographical Regions

                        Central      South       Northeast
            NW India
                         India      Peninsula      India
 Rainfall
Category      Range      Range        Range        Range
            (% of LPA) (% of LPA)   (% of LPA)   (% of LPA)
Below
               105
Normal

                                                              12
Experimental Dynamical LRF System:
        IMD’s Seasonal Forecast Model (SFM)
 Since 2004, IMD has been generating
  experimental dynamical seasonal forecast for
  monsoon rainfall using seasonal forecasting
  model (SFM) originally developed by ECPC.
 Now the system generates global monthly and
  seasonal forecasts (for next 5 months) in
  every calendar month of the year. First such
  LRF system in India.
 Model run for 5 months. For monsoon season
  - ‘0’ lag to ‘5 months’ lag
 10 Ensembles - Initial conditions of first 10
  days of each month (NCEP reanalysis)
 Forecasted SST from NCEP CFSV2 as
  boundary conditions (40 ensemble member
  from first 10 days).
 The model showed some useful skill for the
  monsoon season during hindcast mode (1982-
  2011).
Monsoon Mission Experimental Dynamical Model Forecasting
                 System: CFS V2 (T382)

    Under Monsoon Mission was recently
  launched by the ESSO with an objective to
  improve the monsoon forecasts over the
  country in short range to long range time
  scales.

    The latest high resolution research version
  of the coupled model (Climate Forecast
  System (CFS) of NCEP, USA Version-2)
  was implemented at the ESSO-IITM, Pune.

    To generate the experimental update
  forecast for the 2014 SW Monsoon season
  rainfall, the April initial conditions were used.

    The model shows a moderate skill.

                                                      14
    29th June, 2010
Other National Climate Research Centers
         That Provide Experimental LRF

  Indian Institute of Science (IISc), Bangalore,
  Space Applications Centre (SAC), Ahmedabad,
  Centre for Mathematical Modelling and Computer
  Simulation (CMMACS), Bangalore,
  National Centre for Medium Range Weather
  Forecasting (NCMRWF), Noida and
  Center for Development of Advanced Computing
  (C-DAC), Pune.
  Centre for Disaster Mitigation, Jain University,
  Bangalore.

13-Jun-14
International Climate Research Centers
           That Provide Experimental LRF
World Meteorological Organization (WMO)’s Lead Centre
for Long Range Forecasting - Multi-Model Ensemble
(LRFMME), Korea – Forecast from 12 Global Producing
Centers of LRF
National Centers for Environmental Prediction (NCEP),
USA
 International Research Institute for Climate and Society
(IRI), USA
Meteorological Office, UK,
European Center for Medium Range Weather Forecasts
(ECMWF), UK
Meteo France
Asian-Pacific Economic Cooperation (APEC) Climate
Centre, Korea
Japan Meteorological Agency (JMA)

13-Jun-14
Status of Some Important Factors that
    Having Influence on Monsoon

                                   13-Jun-14
Global SST Departures (oC) and
                           ENSO Conditions over Pacific

 During the last four weeks, above-average
 equatorial SSTs were observed across the
 Pacific, near Indonesia, in the western
 Indian Ocean and in the eastern Atlantic
 Ocean.                                                                     During April through mid-May the observed
El Niño/ La Niña events tend to develop during the period Apr-Jun and
                                                                            ENSO conditions moved from warm-neutral to
  .
•Tend to reach their maximum strength during Dec-Feb                        the borderline of a weak El Niño condition.
•Typically persist for 9-12 months, though occasionally persisting for up
to 2 years
•Typically recur every 2 to 7 years
ESSO-IITM CFS2 Forecast of SST Anomaly: Based
          on April IC (51 ensembles)

  The ESSO-IITM model indicate a continued warming trend, leading to a
  moderate El Niño conditions during the monsoon season with a probability of
  around 70%.

                                                                           19
Latest Model Forecast for
        ENSO Conditions over Pacific

Most of the international ENSO prediction models also indicate about
70% chance of El Niño conditions to develop during the 2014 summer
monsoon season.

                                                                  13-Jun-14
El Nino Vs Monsoon
                                                     In general, Indian SW monsoon
                                           El Nino
       Jun    Jul    Aug    Sep    JJAS
                                          strength
                                                     is weaker than normal during
Year                                                 the El Nino years. During the
1951   86.4   81.1   87.9   67.1   81.3     ME       period 1951-2014, there were 14
1953   101    112    119    100    110      WE
1957   89.2   101    113    77.9   97.6
                                                     El Nino years and during 8 of
                                            SE
1963   88.4   84.7   122    94.2   97.9     ME
                                                     these years ISMR was below
1965   66.7   95.2   77.3   79.2   81.8     SE       normal indicating that there is
1969   76.5   107    106    103    100      WE       no one to one association
1972   73.3   68.8   85.9   76.4   76.1     SE       between EL Nino and ISMR.
1982   83.2   76.9   109    67.8   85.5     ME
                                                     However there is stronger
1987   78.4   71.2   96.3   74.9   80.6     SE
1991   109    91.3   95.5   66.2   90.7
                                                     inverse relationship between
                                            ME
1997   106    98.4   109    93.9   102      SE
                                                     El Nino and rainfall during later
2002   109    45.8   98.3   87.1   80.8     ME       half of the monsoon season
2004   99.2   80.1   95.7   70     86.2     WE       (particularly with September
2009   52.8   95.7   73.5   79.8   78.2     WE       rainfall)

                                                                             13-Jun-14
Composite Rainfall Anomaly: El NINO Years

   During El Nino years, in general, most parts of the
   country except northeast India receive below normal
   rainfall anomalies. The impact is more over northwest
   India and central India.

                                                           13-Jun-14
Indian Ocean Dipole

IOD forecast: A neutral state in the tropical Indian
Ocean in 2014.
 13-Jun-14
Monthly Snow Cover Area - 2014
                                        Departure from normal
        December 2013                   January 2014           February 2014                  March 2014

                                                                                    Data source:
                                                                                    RUTGERS UNIVERSITY

During all the month from September 2013 to March 2013 except January and March 2014, the snow-covered area
averaged over the NH was normal to slightly above normal with highest anomalies observed during October 2013. The
snow-covered area averaged over the NH during January and March 2014 was less than normal with the March NH snow-
covered area being 6th lowest among the March months of the last 48 years. The NH snow cover during winter and
spring has a general negative relationship with the subsequent Asian summer monsoon.
                                                                                                 13-Jun-14
SW Monsoon 2014 ?
                             31-YEAR MOVING AVERAGE OF SEASONAL
                                      MONSOON RAINFALL
                       4
                       3
RAINFALL ANOMALY (%

                       2
   DEP. FROM LPA)

                       1
                       0
                      -1
                      -2
                      -3               y = 2E-08x5 - 4E-06x4 + 0.0003x3 - 0.0059x2 - 0.0218x
                                                           R² = 0.7714
                      -4
                           1905
                           1910
                           1915
                           1920
                           1925
                           1930
                           1935
                           1940
                           1945
                           1950
                           1955
                           1960
                           1965
                           1970
                           1975
                           1980
                           1985
                           1990
                           1995
                           2000
                           2005
                           2010
                           2015
                                YEAR ENDING 31-YEAR SLIDING WINDOW
                                     Negative side of the normal

                 13-Jun-14
Thank you
You can also read