Latent heat for ED2

[Viskari]

As I was going over the output from ED2 as presented by pecan, I realized that ED2 doesn't actually give out latent heat, but the amount of water evaporated and that pecan doesn't currently convert that to energy.

So I thought to ask, before I start adding anything to the code, does pecan have that conversion available? Or should I add it there myself?

[dlebauer]

I don't think so but it would probably be in / should go in
data.atmosphere/R/metutils.R
On Fri, Apr 1, 2016 at 9:42 AM Viskari [email protected] wrote:

As I was going over the output from ED2 as presented by pecan, I realized
that ED2 doesn't actually give out latent heat, but the amount of water
evaporated and that pecan doesn't currently convert that to energy.

So I thought to ask, before I start adding anything to the code, does
pecan have that conversion available? Or should I add it there myself?

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#774

[mdietze]

Ok, so there's definitely an inconsistency here within model2netcdf.ED2 because on line 281 it has what appears to be the correct terms:

out <- add(getHdf5Data(ncT, 'FMEAN_VAPOR_LC_PY')+getHdf5Data(ncT, 'FMEAN_VAPOR_WC_PY')+getHdf5Data(ncT, 'FMEAN_VAPOR_GC_PY'),28,row, yrs[y]) ## Qle

but in the other version, on line 412, it only uses evaporation, which is seems wrong because LE involves both evaporation and transpiration

  out <- add(getHdf5Data(ncT, 'AVG_EVAP'),28,row, yrs[y]) ## Qle

And yes, if either or both of those are in moles or mm instead of watts you need to do the conversion: https://github.com/EDmodel/ED2/wiki/Glossary---unit-conversions

[Viskari]

No, I know I need to do the conversion, I was asking is the conversion method already in pecan or do I need to add it there?

[Viskari]

I am having an issue currently getting the conversion working. I think I figured out what the problem is, but I don't know how to fix it.

I created the function below in data.atmosphere/R/metutils.R and recompiled pecan, but when I call to this function in model2netcdf.ED2.R, it causes the that to crash. I assume the issue is with the param E, but how do I do it correctly?

##' Estimate latent heat from evaporated water [kg/s -> W]
##' @title Latent Heat
##' @param E Evaporation [kg/m2s]
##' @export
##' @author Toni Viskari

LHE <- function(E){
2272000*E
}

[dlebauer]

@Viskari the function looks like it should work, e.g. if I put LHE(10) it comes up with 22720000. Do you have any additional information other than the fact that it crashes? What does the log say?

[dlebauer]

P.S. While you are at it I would suggest adding an analogous function to go from evaporation to latent heat, as well as some tests. And perhaps use more informative names ... here are my suggestions

##' @title Convert evaporation rate to latent heat flux
##' 
##' This function converts latent heat flux given in watts from evaporation rate given in mm/s (= kg/m2/s) 
##  The latent heat of vaporization for water (lambda) is 2,264,760 J kg-1, so E * lambda = LH 
##'  @return latent heat flux (LH) in units of Watts/m2 or J/m2/s 
##' @param E Evaporation [kg/m2s]
##' @export
##' @author Toni Viskari
evaporation2latentheat <- function(E){
   LH <- 2272000 * E
   return(LH)
}

##' @title Convert latent heat flux to evaporation rate
##' 
##' This function converts evaporation rate given in mm/s (= kg/m2/s) to latent heat flux 
##  The latent heat of vaporization for water (lambda) is 2,264,760 J kg-1, so E * lambda = LH 
##'  @return Evaporation Rate in units of mm/s or kg/m2/s 
##' @param LH Latent Heat (W/m2)
##' @export
##' @author Toni Viskari, David LeBauer 
latentheat2evaporation <- function(LH){
   E = LH / 2272000
   return(E)
}

PPS Wednesdays are great days for adding new tests ... just put the lines

test_that('conversions between latent heat and evaporation work',{
  expect_equal(evaporation2latentheat(10), 10 * 2272000)
  expect_equal(latentheat2evaporation(10), 10 / 2272000)
  expect_equal(latentheat2evaporation(evaporation2latentheat(1)), 1)
})

in /modules/data.atmosphere/tests/testthat/test.metutils.R

[Viskari]

I just tried to rerun, but there seems to be a database issue with our
server at the moment. When I have the runs redone, I'll put the error log
here.

On Wed, Apr 13, 2016 at 6:17 PM, David LeBauer [email protected]
wrote:

P.S. While you are at it I would suggest adding an analogous function to
go from evaporation to latent heat, as well as some tests. And perhaps use
more informative names ... here are my suggestions

##' @title Convert evaporation rate to latent heat flux##' ##' This function converts latent heat flux given in watts from evaporation rate given in mm/s (= kg/m2/s) ## The latent heat of vaporization for water (lambda) is 2,264,760 J kg-1, so E * lambda = LH ##' @return latent heat flux (LH) in units of Watts/m2 or J/m2/s ##' @param E Evaporation [kg/m2s]##' @export##' @author Toni Viskarievaporation2latentheat <- function(E){
LH <- 2272000 * E
return(LH)
}
##' @title Convert latent heat flux to evaporation rate##' ##' This function converts evaporation rate given in mm/s (= kg/m2/s) to latent heat flux ## The latent heat of vaporization for water (lambda) is 2,264,760 J kg-1, so E * lambda = LH ##' @return Evaporation Rate in units of mm/s or kg/m2/s ##' @param LH Latent Heat (W/m2)##' @export##' @author Toni Viskari, David LeBauer latentheat2evaporation <- function(LH){
E = LH / 2272000
return(E)
}

PPS Wednesdays are great days for adding new tests ... just put the lines

test_that('conversions between latent heat and evaporation work',{
expect_equal(evaporation2latentheat(10), 10 * 2272000)
expect_equal(latentheat2evaporation(10), 10 / 2272000)
expect_equal(latentheat2evaporation(evaporation2latentheat(1)), 1)
})

in /modules/data.atmosphere/tests/testthat/test.metutils.R
https://github.com/PecanProject/pecan/blob/master/modules/data.atmosphere/tests/testthat/test.metutils.R

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#774 (comment)

[serbinsh]

@Viskarihttps://github.com/Viskari Rafael changed around some hostname/IP mapping on the server which messed up PEcAn. He is changing it all back now to get it up and running again.

On Apr 13, 2016, at 8:16 PM, Viskari <[email protected]mailto:[email protected]> wrote:

I just tried to rerun, but there seems to be a database issue with our
server at the moment. When I have the runs redone, I'll put the error log
here.

On Wed, Apr 13, 2016 at 6:17 PM, David LeBauer <[email protected]mailto:[email protected]>
wrote:

P.S. While you are at it I would suggest adding an analogous function to
go from evaporation to latent heat, as well as some tests. And perhaps use
more informative names ... here are my suggestions

##' @title Convert evaporation rate to latent heat flux##' ##' This function converts latent heat flux given in watts from evaporation rate given in mm/s (= kg/m2/s) ## The latent heat of vaporization for water (lambda) is 2,264,760 J kg-1, so E * lambda = LH ##' @return latent heat flux (LH) in units of Watts/m2 or J/m2/s ##' @param E Evaporation [kg/m2s]##' @export##' @author Toni Viskarievaporation2latentheat <- function(E){
LH <- 2272000 * E
return(LH)
}
##' @title Convert latent heat flux to evaporation rate##' ##' This function converts evaporation rate given in mm/s (= kg/m2/s) to latent heat flux ## The latent heat of vaporization for water (lambda) is 2,264,760 J kg-1, so E * lambda = LH ##' @return Evaporation Rate in units of mm/s or kg/m2/s ##' @param LH Latent Heat (W/m2)##' @export##' @author Toni Viskari, David LeBauer latentheat2evaporation <- function(LH){
E = LH / 2272000
return(E)
}

PPS Wednesdays are great days for adding new tests ... just put the lines

test_that('conversions between latent heat and evaporation work',{
expect_equal(evaporation2latentheat(10), 10 * 2272000)
expect_equal(latentheat2evaporation(10), 10 / 2272000)
expect_equal(latentheat2evaporation(evaporation2latentheat(1)), 1)
})

in /modules/data.atmosphere/tests/testthat/test.metutils.R
https://github.com/PecanProject/pecan/blob/master/modules/data.atmosphere/tests/testthat/test.metutils.R

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#774 (comment)

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Reply to this email directly or view it on GitHubhttps://github.com//issues/774#issuecomment-209698250

[serbinsh]

OK @Viskari try it now

[Viskari]

Okay, got everything running now. So the problem with the function that model2netcdf is complaining about not finding it:

[1] "----- Processing year: 2000"
Error: could not find function "LHE"
Execution halted

Do I need to add some additional link to it?

[mdietze]

Did you recompile PEcAn so the package is built, and did you include the package in the dependencies for the ED package?

[Viskari]

I recompiled, but I hadn't added it to the dependencies. Where do you do that addition?

[mdietze]

https://github.com/PecanProject/pecan/blob/master/models/ed/DESCRIPTION

[Viskari]

Okay, second question how do I do the addition? Do I just add the function name or the data module to the dependencies list?

[dlebauer]

Yes

[mdietze]

The package name goes in the dependencies list, not the function name

[github-actions]

This issue is stale because it has been open 365 days with no activity.