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THE AMERICAN MONSOONS AND THEIR ROLE IN THE WATER CYCLE E. Hugo Berbery, Estela Collini, Viviane Silva Department of Meteorology University of Maryland with thanks to Julia Nogu é s-Paegle, Lee Byerle, Brant Liebmann, Rong Fu PACS PI Meeting - Boulder. Outline

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The american monsoons and their role in the water cycle

THE AMERICAN MONSOONS

AND THEIR ROLE IN THE WATER CYCLE

E. Hugo Berbery, Estela Collini, Viviane Silva

Department of Meteorology

University of Maryland

with thanks to

Julia Nogués-Paegle, Lee Byerle, Brant Liebmann, Rong Fu

PACS PI Meeting - Boulder


The american monsoons and their role in the water cycle

  • Outline

  • 1. The North American monsoon and the low-level jets

  • 2. The South American monsoon

    • a. Advective processes

  • b. Surface processes

  • Keywords

  • Low-level Jet

  • Sources of moisture

  • Land surface – atmosphere feedbacks

  • Hydrologic Cycle


  • The american monsoons and their role in the water cycle

    Mississippi

    Basin

    North

    American

    Monsoon

    South American

    Monsoon

    La Plata Basin

    Summer Monsoons

    LLJs

    MCCs

    Impact on large basins

    LS-A feedbacks


    The american monsoons and their role in the water cycle

    Great Plains

    Gulf of California

    Berbery and Fox-Rabinovitz (2003)


    The american monsoons and their role in the water cycle

    Byerle and Paegle

    LLJ and Precipitation Responseto

    Ambient Zonal flow and Orography

    Deviations from Climatology

    wet

    U200 hPa

    Forcing

    Response

    dry

    LLJ

    correlation coefficients shown (JJA 1951-2000)


    The american monsoons and their role in the water cycle

    Byerle and Paegle

    LLJ and Precipitation Responseto

    Ambient Zonal flow and Orography

    Deviations from Climatology

    LLJ

    wet

    U200 hPa

    Forcing

    dry

    Response

    correlation coefficients shown (DJF 1951-2000)


    The american monsoons and their role in the water cycle

    The mechanical blocking of the upstream zonal winds by Andes has a strong control on SALLJ, especially on seasonal and intraseasonal scales:

    Strong northerly SALLJ

    Strong westerly upstream westerly wind to the west of Andes

    Wang and Fu, 2003, J. Climate


    The american monsoons and their role in the water cycle

    Berbery and Barros, 2002: JHM has a strong control on SALLJ, especially on seasonal and intraseasonal scales:


    The american monsoons and their role in the water cycle

    Unlike the Great Plains LLJ, the South American LLJ is present

    throughout the year

    Berbery and Barros, 2002: JHM



    The american monsoons and their role in the water cycle

    Annual cycle of precipitation (mm/day) as a function of the latitude.

    From Berbery and Barros 2002, JHM.


    The eta model
    The Eta model latitude.

    Model Configuration

    • Horizontal resolution:

      80 km and 22 km

      (tests at 48, 25, 15)

    • Vertical resolution:

      38 lyrs (tests w/ 45 lyrs)

    • Initial and boundary conditions:

      AVN; NCEP Reanalyses

    • Further online information and forecasts:http://www.atmos.umd.edu/~berbery/etasam


    The american monsoons and their role in the water cycle

    While there is an excess of model precipitation over the Monsoon region, the Eta model successfully reproduces the day to day variability.

    In the southern region, the model reproduces the variability and magnitude of the precipitation.


    The american monsoons and their role in the water cycle

    Active monsoon Monsoon region, the Eta model successfully reproduces the day to day variability.

    Monsoon break

    -


    The american monsoons and their role in the water cycle

    The structure of the Monsoon region, the Eta model successfully reproduces the day to day variability.

    summer LLJ estimated

    from the Eta at two

    resolutions:

    80 km and 22 km


    The american monsoons and their role in the water cycle

    Composites based on: P > P Monsoon region, the Eta model successfully reproduces the day to day variability.m +1.5 Psd

    Moisture flux at 925 hPA

    V. Silva


    The american monsoons and their role in the water cycle

    Precipitable Water Monsoon region, the Eta model successfully reproduces the day to day variability.


    The american monsoons and their role in the water cycle

    Theta-e Monsoon region, the Eta model successfully reproduces the day to day variability.


    The american monsoons and their role in the water cycle

    Precipitation Monsoon region, the Eta model successfully reproduces the day to day variability.


    The american monsoons and their role in the water cycle

    Runoff Monsoon region, the Eta model successfully reproduces the day to day variability.


    The american monsoons and their role in the water cycle

    The South American monsoon region Monsoon region, the Eta model successfully reproduces the day to day variability.

    Precipitation

    Runoff


    The american monsoons and their role in the water cycle

    Land surface - atmosphere processes Monsoon region, the Eta model successfully reproduces the day to day variability.

    Drier land surface (lower surface latent flux and higher Bowen ratio) during dry and early transition seasons appears to be the cause of strong delay (> 1.5 months) of the wet season onset.

    1979: Early onset

    1984: late onset

    1986: late onset

    1990: normal

    Fu and Li, 2003, J. Theor. & obs. Clim., LBA special issue


    The american monsoons and their role in the water cycle

    Land surface Monsoon region, the Eta model successfully reproduces the day to day variability. Precipitation


    The american monsoons and their role in the water cycle

    Austral Summer Monsoon region, the Eta model successfully reproduces the day to day variability.

    Latent heat

    Sensible heat

    Soil Moisture

    vs

    Surface variables

    Precipitation

    Bowen Ratio

    Each dot represents

    a 15-day average


    The american monsoons and their role in the water cycle

    Schematic of the precipitation-soil moisture feedback Monsoon region, the Eta model successfully reproduces the day to day variability.

    Increased Soil Moisture

    (time scales of 2 weeks or longer)

    Decreased Sensible Heat

    Increased Latent Heat

    Decreased Bowen Ratio

    (and increased Evaporative Fraction)

    Increased Precipitation


    The american monsoons and their role in the water cycle

    Eta model simulations - October 1983 Monsoon region, the Eta model successfully reproduces the day to day variability.

    IC: SM(%) -45, -30, -15, 15, 30, 45

    E. Collini


    The american monsoons and their role in the water cycle

    • Summary Monsoon region, the Eta model successfully reproduces the day to day variability.

    • The role of advective and local processes was discussed and their impact on precipitation and runoff was assessed.

    • Two precipitation regimes whose centers form a dipole pattern were discussed; their active/break periods seem to be associated with lateral shifts of the Low-level Jet east of the Andes.

    • The precipitation-soil moisture interactionsover SAMreveal apositive feedback at time scales larger than ~2 weeks.


    The american monsoons and their role in the water cycle

    The Eta model (2) Monsoon region, the Eta model successfully reproduces the day to day variability.

    Alternative settings:

    Large domain for

    seasonal simulations

    Higher resolution

    domain for studies of hydrologic impacts


    The american monsoons and their role in the water cycle

    VIC Monsoon region, the Eta model successfully reproduces the day to day variability.

    Hydrologic Model

    Input:Runoff + baseflow

    at each grid cell

    Output:River discharge at

    the basin’s exit point


    The american monsoons and their role in the water cycle

    La Plata basin and the river routing model Monsoon region, the Eta model successfully reproduces the day to day variability.

    River routing model resolution: 1/8 degrees