Abstract:

This dataset is generated using the HYbrid Coordinate Ocean Model (HYCOM) for the purpose of uncertainty quantification study in the Ocean General Circulation Modeling (OGCM). The configuration adopted here is similar to the one used operationally by the US Navy for ocean prediction during the period 2003–2014. It has a 4-km horizontal resolution and 20 vertical levels. The computational domain is open along portions of its southern, eastern and northern boundaries, where values are provided by a lower-resolution (1/12◦ vs. 1/25◦) simulation of HYCOM configured for the Atlantic Ocean. The model is forced at the surface by three hourly outputs from the Coupled Ocean/Atmosphere Mesoscale Prediction (COAMP) System, which has a 27-km resolution. For the present study, the ocean circulation in the Gulf of Mexico between May-01 and May-30 were simulated using HYCOM with uncertain inputs (characterizing both random initial and wind forcing conditions). These simulations were run on Carver at the National Energy Research Scientific Computing Center (NERSC) during Sep 2014 and early 2015. A total of 798 HYCOM simulations were generated. This dataset supports the publication: Li, G., Iskandarani, M., Le Hénaff, M., Winokur, J., Le Maître, O.P. and Knio, O.M., 2016. Quantifying initial and wind forcing uncertainties in the Gulf of Mexico. Computational Geosciences, 20(5), pp.1133-1153.

Suggested Citation:

Guotu Li, Mohamed Iskandarani, Matthieu Le Henaff, Justin Winokur, Olivier P. Le Maitre and Omar M. Knio. 2017. HYCOM simulation ensemble for quantifying uncertainties in ocean circulation responses to random initial and wind forcing conditions using Polynomial Chaos (PC) expansion. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7QZ2813

Publications:

Li, G., Iskandarani, M., Hénaff, M. L., Winokur, J., Le Maître, O. P., & Knio, O. M. (2016). Quantifying initial and wind forcing uncertainties in the Gulf of Mexico. Computational Geosciences. doi:10.1007/s10596-016-9581-4

Wang, S., Li, G., Iskandarani, M., Le Hénaff, M., & Knio, O. M. (2018). Verifying and assessing the performance of the perturbation strategy in polynomial chaos ensemble forecasts of the circulation in the Gulf of Mexico. Ocean Modelling, 131, 59–70. doi:10.1016/j.ocemod.2018.09.002

Purpose:

This dataset is generated using the HYbrid Coordinate Ocean Model (HYCOM) for quantifying uncertainties in ocean circulation responses to random initial and wind forcing conditions using Polynomial Chaos (PC) expansion.

Data Parameters and Units:

Each member of the ensemble simulates ocean circulation in the Gulf of Mexico between May-01 and May-30. Each model output is the daily averaged, centered at 12 noon, of the date corresponding to the file name (e.g. archm.2010_121_12.nc is the file corresponding to the 121st day of the year 2010). Each file includes the coordinates of the grid in terms of latitude, longitude, as well as various 2D variables. The files are in NetCDF format. Directory Tree: root/ Readme.txt 00001/ 00002/ ... 00800/ There are 798 subfolders, ranging from 1 to 800 (Note, #559 and #762 are not present). Each subfolder contains HYCOM outputs from the corresponding simulation run. Under each subfolder, there are two text files ("zeta1" and "zeta2"), along with nc files from May-01 to May-30 in 2010. 00xxx/ zeta1 zeta2 archm.2010_121_12.nc archm.2010_122_12.nc ... archm.2010_150_12.nc "zeta1": Contains FOUR random parameters (each one is between -1 and 1), corresponding to random perturbations of initial condition EOF modes (mode 1,2,3,4 respectively) "zeta2": Contains FOUR random parameters (each one is between -1 and 1), corresponding to random perturbations of wind forcing EOF modes (mode 1,2,3,4 respectively) For more information on "zeta1" and "zeta2", please refer to the published paper (Li, G., Iskandarani, M., Le Hénaff, M., Winokur, J., Le Maître, O.P. and Knio, O.M., 2016. Quantifying initial and wind forcing uncertainties in the Gulf of Mexico. Computational Geosciences, 20(5), pp.1133-1153.) Below is a complete list of 2D variables (including brief definitions) in each of the NetCDF files netcdf archm.2010_xxx_12 { dimensions: MT = UNLIMITED ; // (1 currently) Latitude = 385 ; Longitude = 541 ; variables: double MT(MT) ; MT:long_name = "time" ; MT:units = "days since 1900-12-31 00:00:00" ; MT:calendar = "standard" ; MT:axis = "T" ; MT:cell_methods = "mean" ; MT:cell_extent = 1.00278551532033 ; double Date(MT) ; Date:long_name = "date" ; Date:units = "day as %Y%m%d.%f" ; Date:C_format = "%13.4f" ; Date:FORTRAN_format = "(f13.4)" ; Date:cell_methods = "mean" ; Date:cell_extent = 1.00278551532033 ; float Latitude(Latitude) ; Latitude:standard_name = "latitude" ; Latitude:units = "degrees_north" ; Latitude:axis = "Y" ; float Longitude(Longitude) ; Longitude:standard_name = "longitude" ; Longitude:units = "degrees_east" ; Longitude:axis = "X" ; float qtot(MT, Latitude, Longitude) ; qtot:coordinates = "Date" ; qtot:standard_name = "surface_downward_heat_flux_in_air" ; qtot:units = "w/m2" ; qtot:_FillValue = 1.267651e+30f ; qtot:valid_range = -350.8495f, 315.9829f ; qtot:long_name = " surf. heat flux mean [20.1H]" ; float emp(MT, Latitude, Longitude) ; emp:coordinates = "Date" ; emp:standard_name = "water_flux_into_ocean" ; emp:units = "kg/m2/s" ; emp:_FillValue = 1.267651e+30f ; emp:valid_range = -0.0002291202f, 0.1440809f ; emp:long_name = "surf. water flux mean [20.1H]" ; float surface_temperature_trend(MT, Latitude, Longitude) ; surface_temperature_trend:coordinates = "Date" ; surface_temperature_trend:units = "degC/day" ; surface_temperature_trend:_FillValue = 1.267651e+30f ; surface_temperature_trend:valid_range = -5.895815f, 4.447201f ; surface_temperature_trend:long_name = "surf. temp. trend mean [20.1H]" ; float surface_salinity_trend(MT, Latitude, Longitude) ; surface_salinity_trend:coordinates = "Date" ; surface_salinity_trend:units = "psu/day" ; surface_salinity_trend:_FillValue = 1.267651e+30f ; surface_salinity_trend:valid_range = -150.5229f, 0.5580279f ; surface_salinity_trend:long_name = "surf. saln. trend mean [20.1H]" ; float ssh(MT, Latitude, Longitude) ; ssh:coordinates = "Date" ; ssh:standard_name = "sea_surface_elevation" ; ssh:units = "m" ; ssh:_FillValue = 1.267651e+30f ; ssh:valid_range = -0.4567478f, 0.7161824f ; ssh:long_name = "sea surf. height mean [20.1H]" ; float mixed_layer_u_velocity(MT, Latitude, Longitude) ; mixed_layer_u_velocity:coordinates = "Date" ; mixed_layer_u_velocity:units = "m/s" ; mixed_layer_u_velocity:_FillValue = 1.267651e+30f ; mixed_layer_u_velocity:valid_range = -0.8840337f, 2.308302f ; mixed_layer_u_velocity:long_name = "mix.l. u-velocity mean [20.1H]" ; float mixed_layer_v_velocity(MT, Latitude, Longitude) ; mixed_layer_v_velocity:coordinates = "Date" ; mixed_layer_v_velocity:units = "m/s" ; mixed_layer_v_velocity:_FillValue = 1.267651e+30f ; mixed_layer_v_velocity:valid_range = -1.352656f, 2.148376f ; mixed_layer_v_velocity:long_name = " mixl. v-velocity mean [20.1H]" ; float surface_boundary_layer_thickness(MT, Latitude, Longitude) ; surface_boundary_layer_thickness:coordinates = "Date" ; surface_boundary_layer_thickness:units = "m" ; surface_boundary_layer_thickness:_FillValue = 1.267651e+30f ; surface_boundary_layer_thickness:valid_range = 0.9738244f, 40.72499f ; surface_boundary_layer_thickness:long_name = "bnd.layr.thickness mean [20.1H]" ; float mixed_layer_thickness(MT, Latitude, Longitude) ; mixed_layer_thickness:coordinates = "Date" ; mixed_layer_thickness:standard_name = "ocean_mixed_layer_thickness" ; mixed_layer_thickness:units = "m" ; mixed_layer_thickness:_FillValue = 1.267651e+30f ; mixed_layer_thickness:valid_range = 1.257391f, 119.4817f ; mixed_layer_thickness:long_name = "mix.layr.thickness mean [20.1H]" ; float mixed_layer_temperature(MT, Latitude, Longitude) ; mixed_layer_temperature:coordinates = "Date" ; mixed_layer_temperature:units = "degC" ; mixed_layer_temperature:_FillValue = 1.267651e+30f ; mixed_layer_temperature:valid_range = 20.11741f, 31.94443f ; mixed_layer_temperature:long_name = "mix.layr.temp mean [20.1H]" ; float mixed_layer_salinity(MT, Latitude, Longitude) ; mixed_layer_salinity:coordinates = "Date" ; mixed_layer_salinity:units = "psu" ; mixed_layer_salinity:_FillValue = 1.267651e+30f ; mixed_layer_salinity:valid_range = 0.1879668f, 39.97345f ; mixed_layer_salinity:long_name = "mix.layr.saln mean [20.1H]" ; float mixed_layer_density(MT, Latitude, Longitude) ; mixed_layer_density:coordinates = "Date" ; mixed_layer_density:units = "sigma" ; mixed_layer_density:_FillValue = 1.267651e+30f ; mixed_layer_density:valid_range = -2.953192f, 25.57206f ; mixed_layer_density:long_name = "mix.layr.dens mean [20.1H]" ; // global attributes: :Conventions = "CF-1.0" ; :title = "HYCOM GTEST2 Experiments" ; :institution = "CCS-RSMAS" ; :source = "HYCOM mean archive file" ; :experiment = "20.1" ; :history = "archv2ncdf2d"

Individual Files: