ut_no2_gc_test

Use synthetic partial columns from GEOS-Chem to obtain cloud-sliced NO2 in the upper troposphere and compare this to UT NO2 obtained if simply average the NO2 mixing ratios from the model over the same pressure range (the “truth”). Both are obtained by Gaussian weighting toward the pressure center.

GEOS-Chem partial columns are obtained over Europe, North America, and China at the GEOS-FP meteorology native resolution (0.25x0.3125) (latxlon) for June-August 2016-2017.

Input options to process the data include the region, the horizontal resolution, and model simulation years.

usage: ut_no2_gc_test.py [-h] [--gc_dir GC_DIR] [--out_dir OUT_DIR]
                     [--resolution RESOLUTION] [--region REGION]
                     [--strat_filter_threshold STRAT_FILTER_THRESHOLD]
                     [--start_date START_DATE]
                     [--end_date END_DATE] [-p PLOT]
                     [--do_temp_correct DO_TEMP_CORRECT]
                     [--apply_cld_frac_filter APPLY_CLD_FRAC_FILTER]
                     [--do_cld_hght_test DO_CLD_HGHT_TEST]

optional arguments:
  -h, --help            show this help message and exit
  --gc_dir GC_DIR
  --out_dir OUT_DIR
  --resolution RESOLUTION
                        Can be 8x10, 4x5, 2x25 or 1x1
  --region REGION       Can be EU, NA, or CH
  --strat_filter_threshold STRAT_FILTER_THRESHOLD
  --start_date START_DATE
  --end_date END_DATE
  -p PLOT, --plot PLOT
  --do_temp_correct DO_TEMP_CORRECT
  --apply_cld_frac_filter APPLY_CLD_FRAC_FILTER
  --do_cld_hght_test DO_CLD_HGHT_TEST
exception uptrop.ut_no2_gc_test.CloudSliceException
exception uptrop.ut_no2_gc_test.DomainIssueException
exception uptrop.ut_no2_gc_test.InvalidRegionException
exception uptrop.ut_no2_gc_test.InvalidResolutionException
exception uptrop.ut_no2_gc_test.ProcessingException
class uptrop.ut_no2_gc_test.GeosChemDay(file_path, temperature_correction=False, cloud_height_test=False)

A class for reading, preprocessing and accessing Geoschem data on a given day

__init__(file_path, temperature_correction=False, cloud_height_test=False)

Reads the data at file_path and returns a GeosChemDay object containing that data

Parameters

  • file_path (str) – Path to the netcdf4 file containing the GeosChem data

  • temperature_correction (bool) – Whether to apply temperature correction

  • cloud_height_test (bool) – Whether to test effect of systematic underestimate in cloud height

Returns

A GeosChemDay class

Return type

GeosChemDay

prepare_no2_pixel(x, y)

Extracts preprocesed no2 from the geoschem pixel at x,y

Parameters

  • x (int) – The x index of the pixel

  • y (int) – The y index of the pixel

class uptrop.ut_no2_gc_test.ProcessedData(region, str_res, strat_thld, do_temperature_correction=False, do_cld_frac_filter=False, do_cld_hght_test=False)

A class for comparing geoschem and tropomi data

__init__(region, str_res, strat_thld, do_temperature_correction=False, do_cld_frac_filter=False, do_cld_hght_test=False)

Creates and returns an instance of ProcessedData for a given region

This class aggregates geoschem data over a grid defined by the define_grid method.

Parameters

  • region (str) – The region to aggregate geoschem over; can be NA, EU or CH.

  • str_res (str) – The resolution of the grid around teh region to analyse; can be 8x10, 4x5, 2x25 or 1x1

  • do_temperature_correction (bool) – Whether to perform the temperature correction step

  • do_cld_frac_filter (bool) – Whether to perform fractional filtering of clouds

Returns

A ProcessedData isntance ready to recieve data

Return type

ProcessedData

add_slice(i, j, t_cld, t_col_no2, t_mr_no2, t_fr_c, t_grad_no2, t_o3)
Extracts the upper troposphere gc_data, gc_data error, ozone data, ozone error,

and mean cloud pressure for grid square [i,j]

This method uses the cloud-slicing function uptrop.cloud_slice_ut_no2.cldslice Once calculated, the a weighting is derived from cloud pressure. The weighted upper tropospheric gc_data and error is added to the rolling total for this season. If the cloud slicing fails, then the reason is added to loss_count for the end report.

Parameters

  • i (int) – X-index of grid square

  • j (int) – Y-index of grid square

  • t_cld (float) – Tropospheric cloud

  • t_col_no2 (float) – Total (stratosphere+troposphere) column no2

  • t_mr_no2 (float) – NO2 mixing ratio between pmax and pmin

  • t_fr_c (float) – Cloud fraction between pmax and pmin

  • t_grad_no2 (float) – NO2 gradient between pmax and pmin in pptv/hPa

  • t_o3 (float) – O3 mixing ratio to test influence from stratosphere

define_grid(region, str_res)

Defines a grid based on a set of regional bounding boxes and a resolution

Parameters

  • region (str) – The region to aggregate geoschem over; can be NA, EU or CH.

  • str_res (str) – The resolution of the grid around the region to analyse; can be 8x10, 4x5, 2x25 or 1x1

get_weighted_mean()

Applies weighting to the aggregated means.

plot_data()

Plots the present state of the gridded data

print_data_report()

Prints a set of reasons for missing data

process_geoschem_day(file_path)

Aggregates geoschem data into the processing grid for a file on a given day.

Calls regrid_and_process for each pixel in the geoschem file, then calls process_grid_square for each square of the grid

Parameters

file_path (str) – Path to the geoschem file to load into the processing grid

regrid_and_process(x, y, gc_data)

Inserts data from pixel x,y from geoschem data into the appropriate grid cell

Parameters

  • x (int) – X index of geoschem grid cell

  • y (int) – Y index of geoschem grid cell

  • gc_data (GeosChemDay) – An instance of GeosChemDay data

save_to_netcdf(out_path)

Saves the present state of the grid to a netCDF4 file

Parameters

out_path (str) – Path to the output file