Noah mp snow update

[cenlinhe]

TYPE: enhancement, new feature

KEYWORDS: Noah-MP, snow, MPTABLE, parameter

SOURCE: Cenlin He (NCAR/RAL)

DESCRIPTION OF CHANGES:
Several Noah-MP snow-related aspects have been updated to improve snow simulations:
(1) Add snow retention process at the snowpack bottom to improve streamflow modeling (also to be consistent with National Water Model updates)
(2) Modify wind-canopy absorption coefficient (CWPVT) parameter values in MPTABLE to be vegetation dependent based on Goudriaan1977; previous values are incorrect.
(3) Bring hard-coded snow emissivity of 1.0 to a global tunable MPTABLE parameter, and set to 0.95 to improve WRF surface temperature simulation
(4) Bring hard-coded constant parameter (i.e., 2.5*z0, z0=0.002m) in snow cover formulation to a vegetation-dependent tunable SCFFAC parameter in MPTABLE; values are currently optimized to improve SWE and surface albedo modeling by comparing with SNOTEL and MODIS observations.
(5) Update MFSNO in snow cover formulation with optimized vegetation-dependent MFSNO values based on SNOTEL SWE & MODIS SCF & surface albedo comparison
(6) Add wet-bulb temperature snow-rain partitioning scheme (OPT_SNF=5) based on Wang et al. 2019 GRL
(7) Fix an issue for bulk leaf boundary layer resistance (RB) value range (>100) in RAGRB; Now using more realistic range (5~50)
(8) Add additional QRAIN (rainfall on the ground) output variable (similar to QSNOW) for Noah-MP only.

LIST OF MODIFIED FILES: list of changed files (use git diff --name-status develop to get formatted list)
Compared with the WRF develop branch, the following files are changed:
M Registry/Registry.EM_COMMON
M Registry/Registry.NMM
M Registry/registry.noahmp
M dyn_em/module_first_rk_step_part1.F
M dyn_em/start_em.F
M dyn_nmm/module_PHYSICS_CALLS.F
M dyn_nmm/start_domain_nmm.F
M phys/module_physics_init.F
M phys/module_sf_noahmpdrv.F
M phys/module_sf_noahmplsm.F
M phys/module_surface_driver.F
M run/MPTABLE.TBL
M wrftladj/module_physics_init_ad.F
M wrftladj/module_physics_init_tl.F
M wrftladj/start_em_ad.F
M wrftladj/start_em_tl.Fq

TESTS CONDUCTED:

1. Conducted compilation and official em_real simulation tests with successful results in Cheyenne (by Cenlin He, NCAR)

RELEASE NOTE: These Noah-MP updates include several snow-relevant enhancements and new features to improve snow simulations based on NCAR Noah-MP LSM team tests. The publication is still under development. Snow improvements by this code update include: (1) new snow retention process improves streamflow modeling (tested with Noah-MP in National Water Model); (2) optimized parameter values for snow cover parameters (SCFFAC & MFSNO) improve snow water equivalent (SWE), snow depth, and surface albedo simulation; (3) new snow emissivity value improves WRF surface temperature simulation; (4) new wet-bulb temperature snow-rain partitioning scheme (OPT_SNF=5) improves SWE simulation see Wang et al. 2019 GRL; (5) enhanced flexibility of tuning model parameters by bringing the above-mentioned parameters from hard-coded values to MPTABLE; (6) Fix the incorrect values for wind-canopy absorption coefficient (CWPVT) parameter and the unrealistic value range of bulk leaf boundary layer resistance (RB).

[weiwangncar]

@cenlinhe Can you add the kind of improvement you found in your tests in the RELEASE NOTES?

[cenlinhe]

@cenlinhe Can you add the kind of improvement you found in your tests in the RELEASE NOTES?

I will include it. Thanks.

[dudhia]

Since many more files are affected by adding qrainxy, can that be separated into a different PR?

[cenlinhe]

Since many more files are affected by adding qrainxy, can that be separated into a different PR?

I have that in one of the commits. Is there an easy way to separate out that specific commit?

[dudhia]

It can be removed from the first commit which can be the large one, then it won't matter if the second commit still includes the first changes. Or you can create the small commit first and then add this one after it is merged. Jimy

…

On Wed, Feb 3, 2021 at 12:22 PM Cenlin_He ***@***.***> wrote: Since many more files are affected by adding qrainxy, can that be separated into a different PR? I have that in one of the commits. Is there an easy way to separate out that specific commit? — You are receiving this because your review was requested. Reply to this email directly, view it on GitHub <#1345 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEIZ77CNLVDPKTHRE2VHYSLS5GOK3ANCNFSM4VHN4XVQ> .

[davegill]

@cenlinhe @dudhia @weiwangncar
Would you provide a simple before vs after figure for us. The changes are too massive for us to objectively review. We would like just a short couple of sentences that demonstrate that the modifications are improving the simulation.

[cenlinhe]

@cenlinhe @dudhia @weiwangncar
Would you provide a simple before vs after figure for us. The changes are too massive for us to objectively review. We would like just a short couple of sentences that demonstrate that the modifications are improving the simulation.

The short description of these improvements are summarized in the release note in the PR message above. I will send a few simple figures showing the improvement to all of you soon.

[cenlinhe]

@weiwangncar @dudhia @davegill As Jimy suggested, I have separated this PR to two new PRs (#1403 and #1405), so I am going to close this PR here.

[cenlinhe]

As Jimy suggested, this original PR (#1345) has been separated into two new ones (#1403 and #1405). As Dave requested, here I attached a few simple figures showing the WRF snow simulation improvement after the Noah-MP snow updates (#1403). Thanks. Cenlin

…

On Tue, Feb 9, 2021 at 1:57 PM Dave Gill ***@***.***> wrote: @cenlinhe <https://github.com/cenlinhe> @dudhia <https://github.com/dudhia> @weiwangncar <https://github.com/weiwangncar> Would you provide a simple before vs after figure for us. The changes are too massive for us to objectively review. We would like just a short couple of sentences that demonstrate that the modifications are improving the simulation. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1345 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AKLAFXA6W43AF3RDEOU2FBTS6GOSNANCNFSM4VHN4XVQ> .

-- Cenlin He, Ph.D. Project Scientist Research Application Lab (RAL) National Center for Atmospheric Research (NCAR) Boulder, CO 80301, USA Email: [email protected] —— *My working day may not be your working day. Please do not feel obliged to reply to this email outside of your normal working hours.*