Forcing Data and Hydrological Parameters

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Datasets Description
Soil hydraulic parameters (i.e. saturated hydraulic conductivity, porosity, field capacity and wilting point) were extracted in ArcGIS from the STATSGO database. The values for the vertical the top 11 standard soil layers in STATSGO are provided.  The standard soil layers defined in STATSGO are given in Table 2. Space-time varying land surface properties such as broadband albedo, broadband emissivity, fractional vegetation coverage and leaf area index are derived from MODIS products (Table 3) . The original products are re-projected and composited to the study area, bi-linearly interpolated to basin grids, and then linearly interpolated into hourly time steps. Quality-control and temporal filtering for these landscape attributes data are performed to reduce the discontinuity caused by cloud contamination. The atmospheric forcing data are extracted from the North American Regional Reanalysis (NARR) products originally at 32-km spatial resolution and 3-hour temporal resolution. Elevation adjustments and corrections to near-surface variables are applied between NARR envelope terrain and local terrain at every time-step based on predicted atmospheric conditions (e.g. using dynamic lapse rates). Special bias corrections for downward shortwave radiation are applied through dynamical adjustment, accounting for localized elevation and topographic effects. The temporal interpolation for shortwave radiation is integrated in the topographic correction to capture the local diurnal solar cycle based on solar zenith angle. Precipitation is generated from NCEP/EMC 4KM Gridded Data (GRIB) Stage IV hourly data using bi-linear interpolation and orographic corrections. Integration of Stage IV data with precipitation observations from research networks in the region provides dynamic relationships for improving precipitation accuracy in mountainous terrain.    

Table 1 Summary of the datasets (N=Row, M=Col, T=Time step)

Data Source

Input Fields

Variable Name

SIZE

FORMAT

Unit

Soil Parameters

(STATSGO )

Saturated hydraulic conductivity

HydroCond.txt

N×M

ASCII

m/s

Porosity

Poro.txt

N×M

ASCII

m 3 /m 3

Field capacity

FieldCapa.txt

N×M

ASCII

m 3 /m 3

Wilting point

WiltPot.txt

N×M

ASCII

m 3 /m 3

Landscape Attributes Datasets (MODIS)

Albedo

Albedo.bin

N×M×T

BIN

-

Emissivity

Emissivity.bin

N×M×T

BIN

-

Fractional vegetation coverage  

CV.bin

N×M×T

BIN

-  

Leaf area index

LAI.bin

N×M×T

BIN

-

Atmospheric Forcing Datasets (NARR)

Specific humidity at 10m ABG

SpecHumi_10m.bin

N×M×T

BIN

kg/kg

Air temperature at 10m ABG

AirTemp_10m.bin

N×M×T

BIN

K

Air pressure at 10m ABG

AirPressure_10m.bin

N×M×T

BIN

mb

Wind velocity at 10m ABG

WindSpeed_10m.bin

N×M×T

BIN

m/s

Incoming longwave radiation at surface

DLWR_surf.bin

N×M×T

BIN

W/m 2

Incoming shortwave radiation at surface

DSWR_surf.bin

N×M×T

BIN

W/m 2

Precipitation

(Stage IV)

Precipitation  

Precipitation.bin

N×M×T

BIN

mm/hr  

Table 2 Soil layers defined in STATSGO

Layer    

Thickness      

Depth to Top   

Depth to Bottom

1

5cm(2in)

0cm(0in)

5cm(2in)

2

5cm(2in)

5cm(2in)

10cm(4in)

3

10cm(4in)

10cm(4in)

20cm(8in)

4

10cm(4in)

20cm(8in)

30cm(12in)

5

10cm(4in)

30cm(12in)

40cm(16in)

6

20cm(8in)

40cm(16in)

60cm(24in)

7

20cm(8in)

60cm(24in)

80cm(31in)

8

20cm(8in)

80cm(31in)

100cm(39in)

9

50cm(20in)

100cm(39in)

150cm(59in)

10

50cm(20in)

150cm(59in)

200cm(79in)

11

50cm(20in)

200cm(79in)

250cm(98in)

Table 3 Summary of the MODIS Products used in this project

Short name

Platform

MODIS Product

Raster type

Resolution 

Temporal Granularity

MCD15A2

Combined

Leaf Area Index - FPAR

Tile

1000m

8 day

MOD11C2

Terra

Land Surface Temperature & Emissivity

CMG

5600m

8 day

MCD43B1

Combined

BRDF-Albedo Model Parameters

Tile

1000m

8day

(16 days acquisition interval)

MCD12Q1

Combined

Land Cover Type

Tile

500m

Yearly

MOD08_D3

Terra

Atmosphere Daily Global Product

Gridded

1degree

Daily