Introduction to and validation of MM5/VIC modeling system

The PSU/NCAR Mesoscale Model

● a limited-area, nonhydrostatic, terrain-following sigma-coordinate model ● designed to simulate or predict mesoscale atmospheric circulation. ● developed at Penn State and NCAR as a community mesoscale model

Global 5-day MM5 forecasts:

Today's 24 hour precipitation forecast                                           

MM5 modeling system

• The model is supported by several pre- and post-processing programs.

TERRAIN, REGRID: Horizontal interpolation from a latitude-longitude grid to a mesoscale, rectangular domain on either a Mercator, Lambert Conformal, or Polar Stereographic projection.INTERPF: Vertical interpolation from pressure level to model σ-levels.

The PSU/NCAR Mesoscale Model

Precipitation PressureRadiationWind HumidityAir temperature

Sensible heat fluxLatent heat fluxes…

First coupled by Drs. Ruby Leung at Pacific Northwest National Laboratory (PNNL) and Xu Liang at University of California, Berkeley

Modification of coupled MM5/VIC modeling system

PNNL UW

vegetation type: Single Multiple elevation band: Single Multiple Parameters: Soil, veg type dependant cell dependant initialization: Spinning up 3 months Offline VIC

Original VIC driver

vicNl.c

Initialize global parametersInitialize model stateRead in soil parameter Vegetation parameter Snowband parameterRun model in grid cell for all time steps

MM5-VIC

Two important interface subroutines

RDINIT.F : initialize parameters and model state

VICSURF.C : driver for VIC model

RDINIT.F

Allomem

Initialize global parametersRead in vegetation library

DM_DIST_READ

Load in soil parameter veg. parameter snowband param initial conditions(by offline VIC running)

InivicCalled once per

cellPassing initial atmos fluxesPassing parameters into soil_con_vic & veg_con_vicPassing initial soil condition into dist_prcp_struct

VICSURF.C

VICMODELProvide all forcings to drive VIC model for a grid cell, and feedback the boundary conditions to the MM5 model

VIC_bandSingle call to VIC model for each cell

Dist_prec

●●●

(The main physical processes keep the same as original VIC)

Validation with 2004 NAME Field Experiment

Monthly Precipitation Comparison

Negative bias over coastal land region

Monthly Mean Surface Air Temperature Comparison

MM5-VIC

Observation

Seasonal Mean Downward Shortwave Radiation Diurnal Cycle

Arizona

Downward Shortwave RadiationNew Mexico

Downward Shortwave RadiationMexico

Generally positive bias of downward shortwave radiation

Seasonal Mean Surface Air Temperature Diurnal Cycle

Arizona

Surface Air TemperatureNew Mexico

Surface Air Temperature

El PalmitoDurango

Mazatlan

Cienega de Ntr. Sra.

Culiacan

El FuerteHidalgo del Parral

Creel

Tecoripa

Yecora

Mazocauhui

Mesa Tres RiosHuasabas

Surface Air Temperature

Seasonal Mean Precipitation Diurnal Cycle

Coastal region

Precipitation

Mountainous region

Precipitation

Transect I

Precipitation

Transect II

Precipitation

Transect III

Precipitation

II

I

Arizona

SMEX04 Soil Climate Analysis Network (SCAN) Station 2026, Tombstone, Arizona

Diurnal Cycle

First Layer Soil Moisture

Daily Time Series

Precipitation

*Positively biased initial soil wetness condition

SMEX04 Walnut Gulch Experimental Watershed Soil Moisture Network Data,

Tombstone, ArizonaFirst Layer Soil Temperature Diurnal Cycle

First Layer Soil Moisture Daily Timeseries

2004 NAME site at Estacion Obispo, MX

Diurnal Cycle

First Layer Soil Moisture Daily Timeseries

• MM5/VIC Modeling Evaluation of the Influence of Antecedent Soil Moisture on Variability of the North American Monsoon System

Experimental Design:

Winter Precipitation - Monsoon Rainfall feedback hypothesis

Higher (lower) winter precipitation & spring snowpack

More (less) spring & early summer soil moisture

Lower (higher) spring & early summer surface temperature

Weak (strong) monsoon

Hypothesis to be tested by MM5-VIC coupling system:

0

40

80

120

160

1 2 3 4 5 6 7 8 9 10 11

0

40

80

120

160

200

1 2 3 4 5 6 7 8 9 10 11 12

0

40

80

120

160

200

1 2 3 4 5 6 7 8 9 10 11 12

0

40

80

120

160

200

1 2 3 4 5 6 7 8 9 10 11 12

Study Domain

Monsoon regions are defined as in Comrie & Glenn (1998)

Monsoon West

Monsoon South

Monsoon North

Monsoon East

Summary from data analysis● MW monsoon is negatively related with Southwest

winter precipitation. NW Mexico summer monsoon onset date is positively related with Southwest winter precipitation and snow especially for extreme late and early years.

● Spring soil wetness conditions in the SW U.S. and northwestern Mexico are strongly determined by the previous winter’s precipitation, this land memory appears to play some role in the surface thermal condition, then influence the NW Mexico monsoon onset, but seems to contribute little to MW summer monsoon.

● May Z500 anomalies shows strong relationship with May Ts anomaly all over the North America continent, which suggesting that the atmospheric circulation condition may contribute more to the pre-monsoon Ts anomalies than land surface conditions.

Domain

Late Early

Winter precipitation related

region to summer monsoon

MW

MS

Soil Moisture prescribing domain

1

Running Parameters

• Domain Size: 170*170

• Spatial resolution: 20km

• Running timestep: 60 seconds

• Running period: May 1 ~ Sep. 30

• Output: 6 hrly

• Computer timing: ~115hrs if using 20 processors

Experiment DesignInitial soil moisture prescribed at

OctSepAugJulyJune

SM free runningMay 1 ??

Field capacity Wilting point Normal (VIC climatology)

► Running on wet, normal and dry monsoon years to represent different atmospheric circulation conditions

1

► The initial soil wetness condition on May 1st represents winter precipitation condition.

Sensitivity Experiments► Prescribing initial soil moisture (above-normal,

normal, below-normal) in domain 1 on May 1, then let SM free running until October in wet, normal, dry monsoon years respectively.

soil moisture monsoon yearAbove-normal wetNormal normalBelow-normal dry

Totally 9 runs, which may take about 45 days.►

1984

1987 19951979

1993

MSa JJAS Precipitation and Onset

-3

-2

-1

0

1

2

3

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995

MSa and MW JJAS Precipitation1984 1990

199519791973

Wet year: 1984 (much earlier onset than 1990)

Dry year: 1973, 1979, 1995 ??

Wet year, dry year???

dry year: 1995 (with later onset than 1979)With drought produced extended damages to crops and cattle in Northern Mexico documented from newspapers