Hello,
I have been trying to filter harp product NO2 data if the qa_value is > 0.75. Looking at multiple examples online this is what I passed as ‘operations’ to harp.import_product function:
operations = “bin_spatial(1975,38.025,0.01,2355,11.815,0.01);tropospheric_NO2_column_number_density_validity > 75;derive(longitude{longitude});derive(latitude{latitude})”
I am using python for development. When I run it, I keep getting this error: “CLibraryError: variable ‘tropospheric_NO2_column_number_density_validity’ does not exist”.
When I get rid of the tropospheric_NO2_column_number_density_validity from the operations an print the harp product to see the list of variables, this is what I see:
“double datetime_start {time=1} [seconds since 2010-01-01]
float datetime_length [s]
int orbit_index
double sensor_altitude {time=1, latitude=1973, longitude=2353} [m]
double solar_zenith_angle {time=1, latitude=1973, longitude=2353} [degree]
double solar_azimuth_angle {time=1, latitude=1973, longitude=2353} [degree]
double sensor_zenith_angle {time=1, latitude=1973, longitude=2353} [degree]
double sensor_azimuth_angle {time=1, latitude=1973, longitude=2353} [degree]
double pressure_bounds {time=1, latitude=1973, longitude=2353, vertical=34, 2} [Pa]
double tropospheric_NO2_column_number_density {time=1, latitude=1973, longitude=2353} [mol/m^2]
double tropospheric_NO2_column_number_density_amf {time=1, latitude=1973, longitude=2353} []
double NO2_column_number_density {time=1, latitude=1973, longitude=2353} [mol/m^2]
double NO2_column_number_density_amf {time=1, latitude=1973, longitude=2353} []
double stratospheric_NO2_column_number_density {time=1, latitude=1973, longitude=2353} [mol/m^2]
double stratospheric_NO2_column_number_density_amf {time=1, latitude=1973, longitude=2353} []
double NO2_slant_column_number_density {time=1, latitude=1973, longitude=2353} [mol/m^2]
double cloud_fraction {time=1, latitude=1973, longitude=2353} []
double absorbing_aerosol_index {time=1, latitude=1973, longitude=2353} []
double cloud_albedo {time=1, latitude=1973, longitude=2353} []
double cloud_pressure {time=1, latitude=1973, longitude=2353} [Pa]
double surface_albedo {time=1, latitude=1973, longitude=2353} []
double surface_altitude {time=1, latitude=1973, longitude=2353} [m]
double surface_pressure {time=1, latitude=1973, longitude=2353} [Pa]
double surface_meridional_wind_velocity {time=1, latitude=1973, longitude=2353} [m/s]
double surface_zonal_wind_velocity {time=1, latitude=1973, longitude=2353} [m/s]
double sea_ice_fraction {time=1, latitude=1973, longitude=2353} []
double tropopause_pressure {time=1, latitude=1973, longitude=2353} [Pa]
long count {time=1}
float weight {time=1, latitude=1973, longitude=2353}
float solar_zenith_angle_weight {time=1, latitude=1973, longitude=2353}
float solar_azimuth_angle_weight {time=1, latitude=1973, longitude=2353}
float sensor_zenith_angle_weight {time=1, latitude=1973, longitude=2353}
float sensor_azimuth_angle_weight {time=1, latitude=1973, longitude=2353}
float tropospheric_NO2_column_number_density_weight {time=1, latitude=1973, longitude=2353}
float tropospheric_NO2_column_number_density_amf_weight {time=1, latitude=1973, longitude=2353}
float NO2_column_number_density_weight {time=1, latitude=1973, longitude=2353}
float NO2_column_number_density_amf_weight {time=1, latitude=1973, longitude=2353}
float stratospheric_NO2_column_number_density_weight {time=1, latitude=1973, longitude=2353}
float stratospheric_NO2_column_number_density_amf_weight {time=1, latitude=1973, longitude=2353}
float NO2_slant_column_number_density_weight {time=1, latitude=1973, longitude=2353}
float cloud_fraction_weight {time=1, latitude=1973, longitude=2353}
float absorbing_aerosol_index_weight {time=1, latitude=1973, longitude=2353}
float cloud_albedo_weight {time=1, latitude=1973, longitude=2353}
float cloud_pressure_weight {time=1, latitude=1973, longitude=2353}
float surface_albedo_weight {time=1, latitude=1973, longitude=2353}
float tropopause_pressure_weight {time=1, latitude=1973, longitude=2353}
double latitude_bounds {latitude=1973, 2} [degree_north]
double longitude_bounds {longitude=2353, 2} [degree_east]
double longitude {longitude=2353} [degree_east]
double latitude {latitude=1973} [degree_north]”
‘tropospheric_NO2_column_number_density_validity’ is missing and I even tried editing the netCDF for convert all the NO2 values to 0 if the qa_value for that specific location is greater than 0.75. I created a visualisation of the netCDF file after this filtering and it looks like this:
I don’t understand why does the visualisation has boxes of NO2 pixel values. My questions regarding these issues are:
- Why is the harp product missing ‘tropospheric_NO2_column_number_density_validity’ variable?
- What is the workaround for this?
- If editing the netCDF file to filter qa_values before passing it into harp is a workaround, why does the visualisation look strange?
Can anyone please help me with this? I would really appreciate your response!
Thanks!
I have a visualisation of the data now.