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Prarxol

Evapo-transpiration data

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I am preparing "Evapo-transpiration" data for GSSHA model in WMS. I have raster data of Evapo-transpiration. But, I think it wont work with WMS. So, I think I should use Penman or Deardorff method.

Can anyone tell me how to get the required data for "hydrometerological dataset" for above method?

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I am preparing "Evapo-transpiration" data for GSSHA model in WMS. I have raster data of Evapo-transpiration. But, I think it wont work with WMS. So, I think I should use Penman or Deardorff method.

Can anyone tell me how to get the required data for "hydrometerological dataset" for above method?

Try the GSSHA wiki (http://gsshawiki.com/gssha/Continuous:Computation_of_Evaporation_and_Evapo-transpiration). It has tables that should help give you reasonable values. Also tutorial 9 on the GSSHA wiki explains how to create the input files.

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Try the GSSHA wiki (http://gsshawiki.com/gssha/Continuous:Computation_of_Evaporation_and_Evapo-transpiration). It has tables that should help give you reasonable values. Also tutorial 9 on the GSSHA wiki explains how to create the input files.

cameronj,

Thanks for the information. I already looked on those portion. In tutorial 9, it says "Enter the values required for evapotranspiration using the following table 10, or you can find values from the appendix."

In table 10, required data for tutorial are given. For more value, it said to look at Appendix. But, where is that Appendix? I could not find.

Hmet data is spatial or point data? I mean the tutorial didnt tell about the location Hmet data. Is single data file representing the whole watershed? For large watershed, we may get different Hmet data for different area within the watershed. In that case, what should we do?

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cameronj,

Thanks for the information. I already looked on those portion. In tutorial 9, it says "Enter the values required for evapotranspiration using the following table 10, or you can find values from the appendix."

In table 10, required data for tutorial are given. For more value, it said to look at Appendix. But, where is that Appendix? I could not find.

Hmet data is spatial or point data? I mean the tutorial didnt tell about the location Hmet data. Is single data file representing the whole watershed? For large watershed, we may get different Hmet data for different area within the watershed. In that case, what should we do?

Prarxol,

Section 9.4.1 of this link has the tables you need for all the variables, except wilting point which can be found here. You may need to scroll down a bit to see all the tables.

Hmet info can be found here.

To answer where you can get data, taken from the wiki:

The needed data can be obtained from a variety of sources including the National Climatic Data Center (NCDC) and commercial vendors (such as Earth Info). All seven parameters are contained in data sets referred to as Surface Airways data by most sources. These data are used to perform evapotranspiration calculations.

Because of the variety of data sources, GSSHA will read the data in a variety of formats. These are:

  • SAMSON, Surface Airways, and U.S. Army Engineer Research and Development Center/WES. The SAMSON format is developed for the NCDC historical database of Surface Airways data called SAMSON. These data files may be purchased from the NCDC in the form of a CD, which contains all historical data from 1961-1990.
  • If more recent data are required, they can also be purchased from the NCDC in the Surface Airways format. These file formats contain numerous data parameters in addition to the seven required inputs above.
  • All sources of data can be transferred to the WES format containing only the data required by the model. A sample of the ERDC/WES format is shown below. Examples of the other formats can be found in the GSSHA User's Manual.

ET is spatial, taken from wiki:

Calculation of evapo-transpiration requires additional parameter values be assigned to every active grid cell. These parameters may be assigned with either the Mapping Table File, Section 11, or GRASS ASCII maps specified with project cards described in Section 3.8. ET parameters are typically assigned with a combination soil texture/land use (STLU) index map. The Deardorff method requires values of land surface albedo. For the Penman-Monteith method, values of land surface albedo, vegetation height, vegetation canopy resistance, and vegetation transmission coefficient are needed.

Hope this helps :)

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Prarxol,

Section 9.4.1 of this link has the tables you need for all the variables, except wilting point which can be found here. You may need to scroll down a bit to see all the tables.

Hmet info can be found here.

To answer where you can get data, taken from the wiki:

The needed data can be obtained from a variety of sources including the National Climatic Data Center (NCDC) and commercial vendors (such as Earth Info). All seven parameters are contained in data sets referred to as Surface Airways data by most sources. These data are used to perform evapotranspiration calculations.

Because of the variety of data sources, GSSHA will read the data in a variety of formats. These are:

  • SAMSON, Surface Airways, and U.S. Army Engineer Research and Development Center/WES. The SAMSON format is developed for the NCDC historical database of Surface Airways data called SAMSON. These data files may be purchased from the NCDC in the form of a CD, which contains all historical data from 1961-1990.
  • If more recent data are required, they can also be purchased from the NCDC in the Surface Airways format. These file formats contain numerous data parameters in addition to the seven required inputs above.
  • All sources of data can be transferred to the WES format containing only the data required by the model. A sample of the ERDC/WES format is shown below. Examples of the other formats can be found in the GSSHA User's Manual.

ET is spatial, taken from wiki:

Calculation of evapo-transpiration requires additional parameter values be assigned to every active grid cell. These parameters may be assigned with either the Mapping Table File, Section 11, or GRASS ASCII maps specified with project cards described in Section 3.8. ET parameters are typically assigned with a combination soil texture/land use (STLU) index map. The Deardorff method requires values of land surface albedo. For the Penman-Monteith method, values of land surface albedo, vegetation height, vegetation canopy resistance, and vegetation transmission coefficient are needed.

Hope this helps :)

Hello Cameronj,

You made me more clear on the concept. Thank you for that.

But, still I have some question.

HMET data format has:

1. Year (4 digit)

2. Month

3. Day

4. Hour

5. Barometric pressure

6. Relative humidity

.

.

.

etc.

In my watershed, I have 10 weather station (at different portion of watershed). For same date and time, those 10 station gives the info of temp., press., rainfall etc. This mean, I have different HMET data for same date and time.

But, for creating HMET file, I need only one set of data (But I have 10 different sets). In such case, should I create a average data for each parameters ?

Hope you understand my question.

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Hello Cameronj,

You made me more clear on the concept. Thank you for that.

But, still I have some question.

HMET data format has:

1. Year (4 digit)

2. Month

3. Day

4. Hour

5. Barometric pressure

6. Relative humidity

.

.

.

etc.

In my watershed, I have 10 weather station (at different portion of watershed). For same date and time, those 10 station gives the info of temp., press., rainfall etc. This mean, I have different HMET data for same date and time.

But, for creating HMET file, I need only one set of data (But I have 10 different sets). In such case, should I create a average data for each parameters ?

Hope you understand my question.

First, I would email technical support and see if there is a way to spatially vary this across the grid in WMS (I can't find anything online that says this is possible).

If there is not a way to do this, I would not take the average but would take the inverse distance weighted value for the entire watershed for each of the 7 values needed. You could do this in ArcGis pretty quickly by setting up raster grids based on idw interpolation between the points and taking the average value of the raster values that intersect the watershed.

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