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PRECIPITATION-RUNOFF MODELING SYSTEM (PRMS). MODELING OVERVIEW & DAILY MODE COMPONENTS. PRMS Features. Modular Design Deterministic Distributed Parameter Daily and Storm Mode Variable Time Step User Modifiable Optimization and Sensitivity Analysis. PRMS Manual Options. PRMS.
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PRECIPITATION-RUNOFF MODELING SYSTEM(PRMS) MODELING OVERVIEW & DAILY MODE COMPONENTS
PRMS Features • Modular Design • Deterministic • Distributed Parameter • Daily and Storm Mode • Variable Time Step • User Modifiable • Optimization and Sensitivity Analysis
PRMS Variations PRMS_WET PRMS_ISO PRMS_Yakima PRMS_Jena PRMS-MODFLOW
Distributed Parameter Approach Hydrologic Response Units - HRUs HRU Delineation Based on: - Slope - Aspect - Elevation - Vegetation - Soil - Precip Distribution
HRU DELINEATION AND CHARACTERIZATION Grid Cell Hydrologic Response Units (HRUs) Polygon Hydrologic Response Units (HRUs)
Dill Basin, Germany Topography 750 km2 Sub-basins Land Use
PRMS -- HRU Delineation Pixelated Topographic
Relation of HRUs and Subsurface and GW Reservoirs Surface ( 6 hrus ) Subsurface ( 2 reservoirs ) Ground water (1 reservoir)
HRU resolution PRMS SSR resolution GWR resolution
MODEL DRIVING VARIABLES - TEMPERATURE - max and min daily - lapse rate varied monthly or daily - PRECIPITATION - spatial and elevation adjustment - form estimation
MODEL DRIVING VARIABLES - SOLAR RADIATION - measured data extrapolated to slope-aspect of each HRU - when no measured data, then estimated using temperature, precip, and potential solar radiation - max daily temperature procedure - daily temperature range procedure
Precipitation Gage Catch Error vs Wind Speed (Larsen and Peck, 1972) Rain (shield makes little difference) Snow (shielded) Snow (unshielded)
PRECIPITATION For each HRU - DEPTH hru_precip(hru) = precip(hru_psta) * mo_corr_precip(mo) mo_corr_snow(mo) = Snow_correction mo_corr_rain(mo) = Rain_correction
PRECIPITATION For each HRU - FORM (rain, snow, mixture of both) RAIN tmin(hru) > tmax_allsnow tmax(hru) > tmax_allrain(mo) SNOW tmax(hru) <= tmax_allsnow
[ ] tmax(hru) - tmax_allsnow prmx = * adjmix_rain(mo) (tmax(hru) - tmin(hru) PRECIPITATION For each HRU - FORM (rain, snow, mixture of both) MIXTURE OTHER Precipitation Form Variable Snowpack Adjustment
Precip and Temp Distribution Methods • Manual • Auto Elevation Lapse Rate • XYZ • Inverse Distance … PRMS_USGS PRMS_NWCC • Detrended Kriging
SOLAR RADIATION For each HRU daily_potsw(hru) = ( drad(hru) / horad ) * ------------------orad /cos_slp(hru) - drad and horad computed daily for each HRU and a horizontal surface - Missing data computed by obs_tmax - SolarRad relation [obs_tmax - obs_tmin] --> sky cover --> SolarRad relation
DRIVING VARIABLE INPUT SOURCES • Point measurement data • Radar data • Satellite data • Atmospheric model data
INTERCEPTION Net precipitation net_precip = [ hru_precip * (1. - covden)] + (PTF * covden) Throughfall PTF = hru_precip - (max_stor - intcp_stor)----- if [hru_precip > (max_stor - intcp_stor)] PTF = 0.if [hru_precip <= (max_stor - intcp_stor)] Losses from intcp_stor Rain - Free water surface evaporation rate Snow - % of potet rate for sublimation
Transpiration vs Soil Moisture Content and Weather Conditions
Potential Evapotranspiration (potet) - Pan Evaporation potet(hru) = epan_coef(mo) * pan_evap - Hamon potet(hru) = hamon_coef(mo) * dyl2 * vdsat - Jensen - Haise potet(hru) = jh_coef(mo) * --------------- (tavf(hru) - jh_coef_hru) * rin
Computed ET (AET) as function of PET and Soil Texture PRMS to PRMS/MMS SMAV = soil_moist SMAX = soil_moist_max RECHR = soil_rechr REMX = soil_rechr_max
Actual Evapotranspiration (actet) - f ( antecedent conditions, soil type) - Taken first from Recharge Zone & then Lower Zone - actet period ( months transp_beg to transp_end) transp_beg - start actet on HRU when S tmax_sum(hru) > transp_tmax(hru) transp_end - end actet
Point Evapotranspiration Comparison Aspen Park, CO Eddy correlation Jensen-Haise ET, inches
Basin Evapotranspiration Comparison Jensen-Haise RegCM2 Animas River Basin, Colarado WORKSHOP ON REGIONAL CLIMATE PREDICTION AND DOWNSCALING TECHNIQUES FOR SOUTH AMERICA
GW - ET Relations Mirror Lake, NH
SOIL ZONE(Original Version) sroff Recharge Zone (soil_rechr_max) soil_moist_max (rooting depth) Lower Zone excs (soil_moist > soil zone field capacity) excs - soil_to_gw soil_to_gw to subsurface reservoir to ground-water reservoir
Infiltration - DAILY MODE infil(hru) = net_precip(hru) - sroff(hru) - STORM MODE Point Infil (fr) fr = dI/dt = ksat * [1. + (ps / S fr)] Areal Infil (fin) qrp = ( .5 * net_precip2 / fr ) net_precip < fr qrp = net_precip - (.5 * fr) Otherwise fin = net_precip - qrp