UM Model Precipitation for Indian Monsoon: Days to Season Ashis K. - - PowerPoint PPT Presentation

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UM Model Precipitation for Indian Monsoon: Days to Season Ashis K. - - PowerPoint PPT Presentation

Jul 07, 2023 141 likes •852 views

UM Model Precipitation for Indian Monsoon: Days to Season Ashis K. Mitra (With Input from Colleagues at NCMRWF & UKMO/HC) National Centre for Medium Range Weather Forecasting (NCMRWF) Ministry of Earth Sciences (MoES), Noida, UP, India

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UM Model Precipitation for Indian Monsoon: Days to Season

Ashis K. Mitra

(With Input from Colleagues at NCMRWF & UKMO/HC) National Centre for Medium Range Weather Forecasting (NCMRWF) Ministry of Earth Sciences (MoES), Noida, UP, India ashis.mitra@nic.in NERC-MoES Project ‘SAPRISE CWC’ Meeting, Exeter, 24-26 June 2013

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NCMRWF in SAPRISE

Goal : Seamless Assessment from hours-to-season

Carry out diagnostics from Observations, Globa/Regional UM model output to understanding processes contributing monsoon rainfall at various time scales (from hours to a season variability) Data : (i) Gridded observations including NWP Analysis and Reanalysis data (ii) Satellite estimates for proxy observed fields (iii) UM and other model output from hours to a season NCMRWF focus is on model output from initialised runs both in NWP and Coupled Seasonal runs. First few months of the decadal runs will also be analysed. Model Sensitivity Runs at NCMRWF: NCMRWF UM Global/Regional NWP setup (atmosphere only) NCMRWF UM coupled set up (coarse resolution now)

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SAPRISE: Scientific Objectives

  • To investigate driving processes, variability,

predictability and forced changes in South Asian precipitation on multiple time scales. (NCMRWF :Days to a Season for summer Monsoon)

  • A key focus will be on interactions with the

Indian and remote ocean basins and on the local and remote interactions with the dynamic and radiative effects of aerosol.

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Advanced Model for Monsoon Simulation/Prediction ‘South Asian Monsoon System’ is a major component t of ‘Earth Climate System’ Simulating the variability of Monsoon is a benchmark for model development Evaluation and Diagnostics of Monsoon is important for model development

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Specific Objectives

  • 1. Investigate processes responsible for present day

mean, variability and change in South Asia precipitation and test the ability of state-of-the-art climate models to simulate this. Work Package – 1

  • 2. Evaluate the skill of initialized experiments in

predicting South Asia precipitation variability and investigate mechanisms for predictability. Work Package – 2  NCMRWF

  • 1. Investigate changes in South Asia precipitation and

its drivers and interactions in a changing climate. Work Package – 3

  • 2. Provide a seamless assessment and syntheses of

results to advance our understanding of variability, predictability and change in precipitation in South

  • Asia. Work Package - 4
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Scientific Plan: Years 1 & 2

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4 km grid up to 36 hr forecast hourly update 25 km global grid up to 168 hr forecast Unified Model at NCMRWF NWP set-up up to 10 days Same Model for Global/Regional/Mesoscale & Coupled Model – Seamless System 12 km grid up to 48 hr forecast Coupled N96L85O1L75

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Bufr Database Obstore Converter

OPS (27.2) 4D-VAR (27.2) UM (7.9) UM (12 & 4 km) NCMRWF Obs.

NCMRWF Obstore Converter

  • bstore

N512L70 (25 km in Mid lat) Observation Processing 4D-Variational Assimilation Global Model Regional Model

  • Obs. Decoding

The Unified Model (UM) with a horizontal resolution of about 25km & 70 levels in the vertical and the associated 4D-VAR data assimilation system have been implemented. Real time forecasts are being generated daily since May 2012 With data downloaded from UKMO Forecasts with NCMRWF data started from December 2012

 The NWP Setup

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Observation Type Source Format Aircraft NCMRWF

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Sonde NCMRWF

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Satwind NCMRWF

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Scatwind NCMRWF

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GPSRO NCMRWF

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ATOVS NCMRWF BUFR IASI NCMRWF BUFR AIRS NCMRWF BUFR SSMIS UKMO

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SEVIRI Clear UKMO

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GOES Clear UKMO

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UM Data Assimilation System (real-time) at NCMRWF-

Observation Source & Format

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UM Diagnostics/Verification during Monsoon Diagnose the sources and nature of the errors, and providing information that is useful to modellers for targeting model improvements. Numerical experimentation and sensitivity studies

  • f selected rain events (e.g., monsoon onset,

monsoon depressions, cyclones).

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JUN 2012

1 2 3 4 5 6 7 8 1 2 3 4 5 FORECAST DAYS RMSEV GFS UKMO NCUM

JUL 2012

1 2 3 4 5 6 7 8 1 2 3 4 5 FORECAST DAYS RMSEV GFS UKMO NCUM

AUG 2012

1 2 3 4 5 6 7 8 1 2 3 4 5 FORECAST DAYS RMSEV GFS UKMO NCUM

SEP 2012

1 2 3 4 5 6 7 8 1 2 3 4 5 FORECAST DAYS RMSEV GFS UKMO NCUM

Verification of GFS, UKMO and NCUM models during Jun-Sep 2012

Root Mean Square Error (RMSE) of 850 hPa winds(m/s) against Radiosondes over India

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Verification of UKMO, NCUM , GFS models during Monsoon 2012

Global Model forecast errors during monsoon over Indian region

  • 1. U.K. Met Office (UKMO) Unified Model forecasts
  • 2. NCMRWF version of the Unified Model (NCUM) over India,
  • 3. Global Forecasting Systems (GFS T574L64) NCMRWF version
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Verification against respective analyses

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Verification against respective analyses

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Verification against respective analyses

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Verification against respective analyses

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Verification against respective analyses

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Verification against respective analyses

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Verification against respective analyses

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Verification against respective analyses

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Monsoon Low Pressure Systems

  • During JJAS 2012 ten low pressure

systems formed and none of them intensified to form a monsoon depression.

  • There were four low-pressure systems

which lasted long and significantly impacted in terms of heavy rains over the land regions

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Low Pressure systems during Monsoon 2012

VECTOR ERROR (Km) IN THE PRECDICTED TRACK OF THE FOUR SYSTEMS DURING JJAS 2012

100 200 300 400 500 600 700 Day-1 Day-2 Day-3 Day-4 Day-5

Days Error in (Km)

T574 UKMO NCUM

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  • Model Forecast Daily Rainfall (cm/day)

– 1st June – 30th Sept 2012 – T574,UKMO, and NCUM

  • Observed Daily Rainfall (cm/day)

– 1st June – 30th Sept 2012 – IMD-NCMRWF [Merged Sat + Gauge] – 0.5° x 0.5° grid resolution.

  • Focus on Day-1, Day3 and Day5 forecasts
  • Statistical Verification

– 0.5° x 0.5° grids; over Indian land region.

Evaluation of rainfall forecasts

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  • In T574 the rainfall over central

India is overestimated in Day-1 and underestimated in Day-5.

  • Rainfall northern plains is

underestimated in Day-1 and is made up in Day-3 and Day-5.

  • UKMO and NCUM both show-

– Increasing equatorial rain in the western Indian Ocean from Day-1 to Day-5 – Increasing rainfall coverage over Bay of Bengal from Day-1 to Day- 5

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  • RMSE gives the average

magnitude of forecast errors

  • All three models show higher

RMSE over same region of central and eastern India.

  • RMSE is least over dry regions
  • f peninsula and NW India.
  • T574 shows higher errors than

both UKMO and NCUM.

  • Over Northeastern India, all

models and all forecasts indicate large errors.

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Rain-No Rain

  • ETS tells us how well did the

forecast “yes” events correspond to the observed “yes” events (accounting for hits due to chance)?

  • ETS ranges from -1/3 to 1
  • 0 indicates no skill and
  • 1 meaning perfect score.
  • All three models show high skill

along west coast, some skill over the central India extending east to west.

  • Poor/no skill in the NE India and

eastern peninsula (Day-5) is common in all the forecasts

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Rainfall Thresholds

  • Very low skill for rainfall >2 cm/day
  • Both UKMO and NCUM show higher

skill compared to T574

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UKMO Rainfall Forecast Verification (Six Seasons: 2007-2012)

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The criteria chosen for daily anomalies computation based

  • n

IMD observations and daily

  • climatology. Based
  • n this anomalies

dry and wet days during JJAS have been identified

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2007

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2008

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2009

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2010

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2011

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WET DRY All

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Recent Very Heavy Rainfall In Uttarakhand and HP: 16-18 June 2013

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UM Coupled Model setup at NCMRWF

HadGEM3AO [N96L85O1L75] (UM Atmosphere : 1.875 x 1.125 horizontal resolution) Stand alone model/software implementation / test Global NEMO Ocean Model - EU Community Ocean Model CICE - Sea Ice Model , Las Almos lab. USA OASIS Coupler UKMO coupled model Installed: UM 7.6 , NEMO, CICE with OASIS Successful test run of UKMO coupled model including Portability tests 14 years Hindcast 1996 to 2009 completed , JJA period analysed Start date; 09 May , six months integration Observed data: CMAP rainfall , ERA Interim for other parameters Comparisons with NCEP CFSV2 hind-cast data for same period JULES Land surface data assimilation module to be implemented at NCMRWF

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UM Coupled Model Set-up

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UM Coupled Model Set-up

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UM Coupled Model Set-up

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WOCE 2009 1 x 1 1955-2006

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WOCE 2009 1 x 1 1955-2006

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WOCE 2009 1 x 1 1955-2006

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I m proved Physics in GA 3 .0 ( UM 7 .7 ) (Hindcast Results, MO Runs)

( 1 ) Radiation: (a)upgraded treatment of ozone UV absorption (improves warm bias of stratosphere, better stratosphere-troposphere interaction) (b) upgraded solar spectrum , (c)included treatment of cloud in-homogeneity (d) exponential–random cloud overlap ( 2 ) Large-scale precipitation: Modified rainfall speed and prognostic rain formulation ( with a sub–time step of 2 min ) ( 3 ) Convection: Relaxed conditions for the diagnosis of shallow convection, (makes the conditions for the diagnosis of deep convection more stringent) ( 4 ) Land Surface/ hydrology : Replacement of the MOSES-II model with JULES.

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Wet Monsoon

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Dry Monsoon

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NCMRWF Plans with MO & Collaborators

350 TF HPC just arrived, functional from Dec 2013

  • Diagnose the sources and nature of the errors, and providing information

that is useful for targeting model improvements including initial conditions

  • Numerical experimentation and sensitivity studies of selected rain events

(e.g., monsoon onset, monsoon Lows and depressions, Monsoon trough, tropical systems)

  • Study the impact of coupling for improved monsoon model rainfall

variability hours-to-season including ocean initialisation (NEMOVar)

  • Experiments with physical processes including aerosol sensitivity and land-

surface processes

  • Experiments with high resolution coupled model N216L85O25L75
  • Results from NERC-MoES Monsoon Mission Joint Projects
  • Implement Ensemble Prediction Models in NWP and short-term climate
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Thanks