1. 4/25/2017
VIC-CropSyst
Sep 16, 2011
Template I-Grey curve

2. Outline Overview Modeling Approach Data and parameterization
Challenges ahead

3. Overview

4. VIC-CropSyst VIC CropSyst Hydrology Cropping Systems Liang et al, 1994
Stockle and Nelson 1994

5. Overview of Framework

6. Modeling Approach – specific to VIC-CropSyst

7. VIC-CropSyst Model VIC CropSyst 1. Weather (D) 2. Soil Sow date
Soil layer depths
Soil water content
3. Water flux (D)
Infiltrated water
4. Crop type
Irrigation water = Crop Water Demand /irrigation efficiency
Sow date
Crop interception capacity
Crop phenology
Crop uptake (D)
Water stress (D)
Current biomass (D)
Crop Water demand (D)
Harvest day
Crop Yield
D – communicated daily

8. VIC-CropSyst : Coupling Approach
T – Transpiration
IP – Interception
capacity
I – Infiltration
Ir – irrigation
Wd- Water demand
Q – Runoff
Q01 – Drainage from
0 to 1
Q02 – Drainage from
0 to 2
Qb – Baseflow
W0 – water content in 0
W1 – water content in 1
W2 - water content in 2
Tmin, Tmax – daily minimum and maximum temperature
Ws – wind speed
RH – Relative humidity
SR – Solar radiation Qb
Q12 T IP
Redistribute I, W0, W1 and W2 to CropSyst layers Q
Q01
W0,W1, W2
T0, T1, T2, IP, Wd I
CropSyst
VIC Ir
Daily Tmin, Tmax,
Ws, RH, SR, I
VIC – CropSyst interactions
The main difference in the subsurface structure between the two models is the number of subsurface layers. Although VIC is capable of having many layers, it traditionally run with 3 layers (0, 1 and 2). CropSyst has many more subsurface layers that increase with depth.
VIC to CropSyst
-The transpiration amount returned by the CropSyst model is used to update the soil water content of the VIC layers
-Infiltration, surface runoff, drainage between layers, and base flow are estimated by VIC at daily time scale
-The weather data, infiltrated water are passed daily
-soil water contents and soil structure (layer depths) are passed once at the beginning of the season
The CropSyst model finds an appropriate day for sowing the crop and starts simulating the crop growth. At daily time step it returns the water transpired by the crop, the interception capacity, current biomass, water stress and the water demand of the crop. Based on the water demand, VIC adds the irrigation water, which depends on the water availability when running under reduced irrigation scenario. CropSyst also finds the appropriate day after maturity to harvest the crop and returns the crop yield on that day.

9. Invoking CropSyst within VIC gridcell
CropSyst is invoked
Crop 2
CropSyst is invoked
Crop 1
Non-Crop Vegetation
This illustrates an example of land cover distribution within a VIC grid cell. Sub-grid variability in land cover is handled statistically (i.e., each land cover within a grid cell is assigned a percentage of the area occupied by that grid cell.) When the VIC-Cropsyst model is executed, the CropSyst model is invoked only for the sub-grids that are occupied by a crop. The non-crop type land covers are handled by the non-coupled VIC model.
VIC grid cell
(resolution=1/16° ~ 33 km2 )
Within the cell, VIC does not identify the geographical locations of the crops

10. VIC-CropSyst integration - Time view
Total yield,
Biomass etc
Crop 1
At the beginning of each daily time step
To CropSyst
Weather condition
Irrigation- add 20mm if the need ≥ 20 mm
Crop type, Soil
texture
Start looking for sow day
Crop harvest date
VIC grid cell
Crop emerges
Time
This gives a time series view of how the integration works. The text boxes are also surrogates for actual programming interfaces. When the land cover type is identified as a crop, we prepare CropSyst at the beginning of the time loop (this can be actually done anytime before the growing of the crop) by telling it what type of crop is being grown and also give the soil characteristics.
Depending on the management parameter-sowing date, we will ask CropSyst to start the plant dynamics. From this date onwards, we will tell CropSyst at the beginning of each time step, the soil water content, weather condition, CO2 concentration, reference evap. And at the end of the time step, CropSyst returns the updated soil water content, Irrigation need and transpiration.
When it is time for harvesting, we ask CropSyst to harvest and return the total yield, biomass etc.
At the end of each daily time step
From CropSyst
Irrigation need
Transpiration

11. Time view
Crop type 2, Soil
texture
At the beginning of each daily time step
To CropSyst
Weather
Irrigation if needed
Sow date-
Start crop growing
Crop harvest date
Total yield,
Biomass etc
Crop 2
Crop 1
At the beginning of each daily time step
To CropSyst
Weather
Irrigation if needed
Sow date-
Start crop growing
Crop harvest date
Total yield,
Biomass etc
Crop type 1, Soil
texture
First clipping
Second clipping
The crop parameters both physical and management can change between crops within the same VIC grid cell.
This is to show that the management options like sowing date, irrigation practices and harvesting date can change between crops and in theory crop 1 and crop 2 can be the same3 crop but have different management practices.
This is also a good time to emphasize the spatial variability of Crop parameters.
We may have to mention that as a first step, while the parameterization is still going on, we are building a model that grows only one crop with spatially homogenous parameters.

12. Selective deficit irrigation
- Curtailment cells are identified from the water rights data
-Low value crops are curtailed
before curtailing the high value crops
- Monthly curtailments are disaggregated to grid cell and crop specific reduction in irrigated water
For a low value crop selected for curtailment
Under full irrigation
Under deficit irrigation
Month scale

13. Data and parameterization

14. Input to VIC-CropSyst VIC-CropSyst Met data CropSyst parameter files
Crop specific parameters files
Phenology adjusted files
Soil parameter files
County – gridcell association information
CropSyst parameter files
VIC-CropSyst
Met data
VIC parameter files
Global control file
Veg parameter file
Veg library
Soil data
Snow bands data
Crop library
Crop parameter file

15. Crop Land Data Layers
WSDA – Washington State Department of Agriculture
USDA – US Department of Agriculture

16. Reconciling USDA and WSDA
Crop Code
WSDA name
USDA name
Model name
218
Wheat
WinWheat
210
Missing
SpgWheat
701
Alfalfa, Hay
Alfalfa
1827
Potato
Potatoes
204
Corn, Field
Corn
1208
Pasture_Grass
1401
Apple
Apples
1803
Bean, Dry
DryBeans
1804
Bean, Green
BeanGreen
1824
Pea, Dry
Peas
713
Grass, Hay
GrassHay
1814
Corn, Sweet
SweetCorn
1206
NLCDPasture_Hay
1503
Bluegrass, Seed
BluegrassSeed
703
Alfalfa/Grass, Hay
AlfalfaOrGrassHay
1403
Cherry
CherryOrchard
1207
OtherHays

17. Crops Modeled Major Crops Grape, Juice Grape, Wine Pea, Green Pea, Dry
Sugarbeet
Canola
Onions
Asparagus
Carrots
Squash
Garlic
Spinach
Berries
Grape, Juice
Grass hay
Bluegrass
Hay
Rye grass
Oats
Bean, green
Rye
Barley
Bean, dry
Other Pastures
Winter Wheat
Spring Wheat
Alfalfa
Barley
Potato
Corn
Corn, Sweet
Pasture
Apple
Cherry
Lentil
Mint
Hops
Caneberry
Blueberry
Cranberry
Pear
Peaches
Other Tree fruits
Lentil/Wheat type
Generic Vegetables

18. Crop specific parameters
Each crop has a parameter file
[phenology]
maturity_significant=true
emergence=
flowering=850
peak_LAI=800
filling=950
maturity=1500
senescence=1000
tuber_init=
resolution=day
base_temp=5
cutoff_temp=25
maximum_temp=25 ….
[transpiration]
ET_crop_coef=1.23
max_water_uptake=13
stomatal_closure_leaf_water_pot=-1300
wilt_leaf_water_pot=-2000
[canopy_cover]
initial_cover=0.05
maximum_cover=0.85
mature_green_cover=0.2
mature_total_cover=0.7 …

19. Phenology parameters adjustments

21. Phenology parameters adjustments
Crop parameter file
Downscaled Met data
Crop present in the grid cell?
Calibration
(independent code)
New phenology crop parameter file- adjust is specific to the geographic location of the cell.
This is a pre-processor and creates “xxx_adjusted” file for each crop

22. County yield adjustments
CropSyst yields are dry yields and cannot be directly compared to the NASS values
CropSyst assumes optimum conditions and does not account for losses due to pests, diseases etc
Adjusted based on observed data
Observed yield data available only at county or State scale
Adjustments are currently hard coded

23. CropSyst soil data Current VIC soil data was too course for CropSyst
STATSGO based soil data is used by the CropSyst for estimating the soil properties

24. Input to VIC-CropSyst Met data VIC-CropSyst CropSyst parameter files
Crop specific parameters files
Phenology adjusted files
Soil parameter files
County – gridcell association information
CropSyst parameter files
Met data
VIC-CropSyst
VIC parameter files
Global control file
Veg parameter file
Veg library
Soil data
Snow bands data
Crop library
Crop parameter file

25. Veg parameter file Traditional land cover inputs to VIC
Vegetation library file
Vegetation parameter file
1… … Evergreen Needleleaf
2… … Evergreen Broadleaf …
11…….

26. New parameter files related to crop distribution
Crop library file
Crop parameter file
204 Corn
205 CornUnknown
210 SpgWheat
218 WinWheat
Alfalfa
…..
Crop code
Fraction of the cell
Day of the crop creation
Irrigation identifier
Perennial crop identifier

27. Veg parameter file for VIC-CropSyst
1… … Evergreen Needleleaf …
11…….
204…… Corn
205… CornUnknown
Vegetation library file
Vegetation parameter file
…..

28. Challenges ahead

29. Future work VIC soil data – should be redone
Crop land data layer – discrepancies between data sources must be resolved
Irrigation data for other States
Crop rotation
Conveyance loss is currently not modeled
Groundwater component
Calibration of “VIC-CropSyst”

30. 4/25/2017
THANK YOU!!
Template I-Grey curve