What’s New in VIC 4.0.6

1. What’s New in VIC 4.0.6 Ted Bohn Hydro Seminar October 12, 2007

2. Outline • Updates since 4.0.5 • New Features • Bug Fixes • Backwards-compatibility • How To Get 4.0.6 • Future Plans • VIC 4.1.0/4.1.1

3. New Features • Flexible Output • Write exactly the variables you want to see • Reduce disk usage & run time • Output Aggregation • To any multiple of model TIME_STEP, up to daily • Reduce disk usage & run time • Avoid unnecessary post-processing (by hand) • ALMA Input/Output • Compliance with ALMA standard for model intercomparisons • http://www.lmd.jussieu.fr/~polcher/ALMA/ • Output Headers • Document exactly what’s in your file and how created Important for tsunami

4. Example Global Parameter File Print Headers ALMA output Output Aggregation Number of output files Number of vars in file File prefix Variable name Format code Variable type Flexible Output Multiplier (only used for binary output) This variable has 3 elements, but we just specify it once

5. Resulting Output File Optional Header Number of Records Output Time Step Variable Names ALMA yes/no 3 Elements of OUT_SOIL_MOIST Date printed automatically (not printed for OUTPUT_FORCE option)

6. Headers • Available for binary output files • Available for forcing files produced with the OUTPUT_FORCE option • VIC will automatically detect and skip headers in forcing files (if they start with #) In global parameter file: • PRT_HEADER TRUE • Header • PRT_HEADER FALSE (or not mentioned) • No header

7. ALMA Input • VIC now accepts the following input forcing vars: • SNOWF snowfall rate (kg/m^2s) • RAINF rainfall rate (kg/m^2s) • CRAINF convective rainfall rate (kg/m^2s) • LSRAINF large scale rainfall rate (kg/m^2s) • QAIR specific humidity (kg/kg) • WIND_E zonal wind speed (m/s) • WIND_N meridional wind speed (m/s) • TAIR air temperature per time step (K) • PSURF atmospheric pressure (Pa) http://www.lmd.jussieu.fr/~polcher/ALMA/convention_input_3.html • To see complete list of available input forcing vars, see vicNl_def.h • VIC automatically handles these if they are listed in your global parameter file

8. ALMA Output In global parameter file: • ALMA_OUTPUT TRUE • Moisture fluxes converted from mm/timestep to mm/s • Temperatures converted from C to K • Pressures converted from kPa to Pa • DeltaCC and DeltaH converted from W/m2 to J/m2 • Recommend %.7e output format for ALMA moisture fluxes • ALMA_OUTPUT FALSE (or not mentioned at all) • Default behavior More info on ALMA output conventions: http://www.lmd.jussieu.fr/~polcher/ALMA/convention_output_3.html

9. List of available input forcing vars: vicNl_def.h Variable Name Note: name in your global param file must match this exactly Variable Description

10. List of available output vars: vicNl_def.h Variable Name Note: name in your global param file must match this exactly Variable Description Instructions on how to add a new output variable to VIC will be posted on the VIC web site

11. Example Files In the VIC source code folder: • global.param.sample • All available options visible • “Recipes” for flexible output: • output.TRADITIONAL.template • output.OUTPUT_FORCE.template • output.PILPS-2E.ALMA.template • output.OUTPUT_FORCE.ALMA.template • output.LDAS_OUTPUT.template • output.OPTIMIZE.template You can paste the contents of these files into your global param file VIC uses these formats automatically; just here for your reference ALMA-compliant formats Historical formats

12. State Files • SAVE_STATE user_def.h option is gone • Now, global param file controls reading/writing state files: • To read an initial state file: INIT_STATE init_state_filename • To save a state file: STATENAME state_file_name STATEYEAR state_year STATEMONTH state_month STATEDAY state_day • State file is written AFTER the FINAL timestep on STATEDAY

13. Bug Fixes BASEFLOW option • Replaces BASEFLOW_NIJSSEN2001 and ARNO_PARAMS options • BASEFLOW ARNO (or not mentioned) • Standard baseflow parameters in the soil parameter file • BASEFLOW NIJSSEN2001 • Baseflow parameters from Nijssen et al 2001 • (rarely needed – only for certain global and/or arctic data sets)

14. Bug Fixes Aerodynamic Resistance Output • Pre 4.0.6: • Value printed was the value before stability correction applied • Aggregated by arithmetic average over veg tiles • Now: • Corrected value • Aggregated by 1/(arithmetic average of conductances)

15. Bug Fixes Baseflow formula • 4.0.4, 4.0.5: typo in non-linear part of formula • Now: fixed • Very little difference in results unless your grid cells commonly experience near-saturation in bottom soil layer

16. Bug Fixes Liquid soil moisture should never be < residual moisture • Occasional reports of invalid soil moisture • Can’t reproduce this • Found & fixed some bugs in code • No difference in results so far • Please let us know if you find soil moisture < residual moisture

17. Bug Fixes For complete list of bug fixes, see README.txt in source code folder

18. Backwards Compatibility You should be able to replace 4.0.5 with 4.0.6 with few or no changes to your parameters Differences: • Replace ARNO_PARAMS and/or BASEFLOW _NIJSSEN2001 with BASEFLOW • State file behavior completely controlled by global param file • State files saved at END of STATEDAY • To read them as initial state files in a later run, start your run on the following day

19. Other Useful Features (not new) Command-line options • vicNl –v • Which version am I running? • vicNl –o • What are the compile-time options (from user_def.h)? (these could be different from what’s currently in user_def.h, if you’ve changed user_def.h but not recompiled VIC) • vicNl –h • List of valid command-line options

20. Other Useful Features (not new) COMPUTE_TREELINE • For use with SNOW_BANDS > 1 • If TRUE, VIC computes the location of the tree line based on lapse rate and mean July air temp • Mean July air temp can be specified in 54th column of soil parameter file • Any bands above the tree line will have tree veg tiles replaced with grass (or veg of your choice) • This can prevent runaway snow packs

21. Other Useful Features (not new) ARC_SOIL option • If specified, VIC will read soil parameters from Arc/Info ascii-format grids

22. Known Bugs • (To be addressed in VIC 4.1) • For multiple snowbands and FULL_ENERGY/FROZEN_SOILS = TRUE, partitioning of water and ice in soil may be wrong • This combination of model modes is not common • Forcing disaggregation & lapsing not consistent within model

23. How to get code • Currently beta-testing VIC 4.0.6 – please help! • Latest beta version available at /usr/local/hydro/build/models/vic/VIC_4.0.6_r1 or ftp.hydro.washington.edu/pub/vic/VIC_4.0.6_Code_beta_r1.tar.gz

24. VIC Web Site: • Documentation • Source code info • and downloads

26. Future Plans • Release VIC 4.0.6: November 1 • Will include updating of web documentation • Hopefully no VIC 4.0.7 • VIC 4.1.0/4.1.1 • Current beta version is 4.1.0_r4 (freeze Oct 19) • Flexible output, output aggregation, ALMA I/O, output headers • Lake model • Spatial frost, spatial snow • Blowing snow • Permafrost • CONTINUE_ON_ERROR • 4.1.0_r5 (freeze Nov 1) • Update to lake model – requires change in lake parameter file format • Kostas’s snow model? • 4.1.1 (release Dec 1?) • Basically 4.1.0_r5 with fixes to any minor bugs found in beta testing

27. Future Plans Known issues in 4.1.0/4.1.1 (probably will be addressed post-4.1.1) • Results different from 4.0.6 - valid? • COMPUTE_TREELINE doesn’t function • For multiple snowbands and FULL_ENERGY/FROZEN_SOILS = TRUE, partitioning of water and ice in soil may be wrong • Forcing disaggregation & lapsing not consistent within model • Others – see VIC web pages for details

28. Best Practices for Running on Cluster • Only write those variables you absolutely need • Aggregate to daily (OUT_STEP 24) whenever possible • If you have a large domain, split it into smaller pieces and run each as a separate job • Write output locally (/state/partition1/……) and only copy output to /raid when job is finished