SCIAMACHY_L2_NADIR_UV9_CHOCHO
Variables
The table below lists the variables that are present in the HARP product that results from an ingestion of SCIAMACHY_L2_NADIR_UV9_CHOCHO
data.
field name 
type 
dimensions 
unit 
description 

datetime_start 
double 
{time} 
[seconds since 20000101] 
measurement start time 
datetime_length 
double 
{time} 
[s] 
measurement integration time 
orbit_index 
int32 
absolute orbit number 

latitude 
double 
{time} 
[degree_north] 
center latitude for each nadir pixel 
longitude 
double 
{time} 
[degree_east] 
center longitude for each nadir pixel 
latitude_bounds 
double 
{time, 4} 
[degree_north] 
corner latitudes for each nadir pixel 
longitude_bounds 
double 
{time, 4} 
[degree_east] 
corner longitudes for each nadir pixel 
solar_zenith_angle 
double 
{time} 
[degree] 
solar zenith angle at top of atmosphere 
viewing_zenith_angle 
double 
{time} 
[degree] 
line of sight zenith angle at top of atmosphere 
relative_azimuth_angle 
double 
{time} 
[degree] 
relative azimuth angle at top of atmosphere 
scan_direction_type 
int8 
{time} 
scan direction for each measurement; enumeration values: forward (0), backward (1), mixed (2) 

C2H2O2_column_number_density 
double 
{time} 
[molec/cm^2] 
C2H2O2 vertical column density 
C2H2O2_column_number_density_uncertainty 
double 
{time} 
[molec/cm^2] 
error on the C2H2O2 vertical column density 
C2H2O2_column_number_density_validity 
int32 
{time} 
flag describing the C2H2O2 vertical column density 

cloud_fraction 
double 
{time} 
[] 
average cloud fraction of footprint 
index 
int32 
{time} 
zerobased index of the sample within the source product 
Ingestion options
The table below lists the available ingestion options for SCIAMACHY_L2
products.
option name 
legal values 
description 

dataset 
nad_uv0_o3, nad_uv1_no2, nad_uv3_bro, nad_uv4_h2co, nad_uv5_so2, nad_uv6_oclo, nad_uv7_so2, nad_uv8_h2o, nad_uv9_chocho, nad_ir0_h2o, nad_ir1_ch4, nad_ir2_n2o, nad_ir3_co, nad_ir4_co2, lim_uv0_o3, lim_uv1_no2, lim_uv3_bro, clouds_aerosol 
the dataset of the L2 product to ingest; each dataset is a combination of nadir/limb choice, retrieval window, and main quantity; option values are ‘nad_uv0_o3’ (default), ‘nad_uv1_no2’, ‘nad_uv3_bro’, ‘nad_uv4_h2co’, ‘nad_uv5_so2’, ‘nad_uv6_oclo’, ‘nad_uv7_so2’, ‘nad_uv8_h2o’, ‘nad_uv9_chocho’, ‘nad_ir0_h2o’, ‘nad_ir1_ch4’, ‘nad_ir2_n2o’, ‘nad_ir3_co’, ‘nad_ir4_co2’, ‘lim_uv0_o3’, ‘lim_uv1_no2’, ‘lim_uv3_bro’, ‘clouds_aerosol’ 
This definition is only applicable when: dataset=nad_uv9_chocho
Mapping description
The table below details where and how each variable was retrieved from the input product.
field name 
mapping description 


datetime_start 
path 
/nad_uv9_chocho[]/dsr_time 
datetime_length 
path 
/nad_uv9_chocho[]/integr_time 
orbit_index 
path 
/mph/abs_orbit 
latitude 
condition 
No coadding needed 
path 
/geolocation_nadir[]/cen_coor_nad/latitude 

description 
center latitude for each nadir pixel 

condition 
Coadding needed and all N geolocations are within a single scan (N is not divisible by 5) 

path 
/geolocation_nadir[]/cor_coor_nad[] 

description 
the latitude of the geographic average of cor_coor_nad[2] and cor_coor_nad[3] of the N/2th pixel 

condition 
Coadding needed of both forward and backward scan pixels (N is divisible by 5) 

path 
/geolocation_nadir[]/cen_coor_nad, /geolocation_nadir[]/cor_coor_nad[] 

description 
the latitude of the geographic average of 1: the geographic average of cor_coor_nad[2] and cor_coor_nad[3] of the second pixel and 2: cen_coor_nad of the Nth pixel 

longitude 
condition 
No coadding needed 
path 
/geolocation_nadir[]/cen_coor_nad/longitude 

description 
center longitude for each nadir pixel 

condition 
Coadding needed and all N geolocations are within a single scan (N is not divisible by 5) 

path 
/geolocation_nadir[]/cor_coor_nad[] 

description 
the longitude of the geographic average of cor_coor_nad[2] and cor_coor_nad[3] of the N/2th pixel 

condition 
Coadding needed of both forward and backward scan pixels (N is divisible by 5) 

path 
/geolocation_nadir[]/cen_coor_nad, /geolocation_nadir[]/cor_coor_nad[] 

description 
the longitude of the geographic average of 1: the geographic average of cor_coor_nad[2] and cor_coor_nad[3] of the second pixel and 2: cen_coor_nad of the Nth pixel 

latitude_bounds 
condition 
No coadding needed 
path 
/geolocation_nadir[]/cor_coor_nad[]/latitude 

description 
corners are rearranged in the following way: 0,2,3,1 

condition 
Coadding needed and all N geolocations are within a single scan (N is not divisible by 5) 

path 
/geolocation_nadir[]/cor_coor_nad[] 

description 
cor_coor_nad[0] and cor_coor_nad[1] are taken from the first pixel and cor_coor_nad[2] and cor_coor_nad[3] are taken from the Nth pixel; corners are rearranged in the following way: 0,2,3,1 

condition 
Coadding needed of both forward and backward scan pixels (N is divisible by 5) 

path 
/geolocation_nadir[]/cor_coor_nad[] 

description 
cor_coor_nad[0] is taken from the first pixel, cor_coor_nad[2] is taken from the fourth pixel, cor_coor_nad[1] is taken from cor_coor_nad[3] of the Nth pixel, and cor_coor_nad[3] is taken from cor_coor_nad[1] from the Nth pixel; corners are rearranged in the following way: 0,2,3,1 

longitude_bounds 
condition 
No coadding needed 
path 
/geolocation_nadir[]/cor_coor_nad[]/longitude 

description 
corners are rearranged in the following way: 0,2,3,1 

condition 
Coadding needed and all N geolocations are within a single scan (N is not divisible by 5) 

path 
/geolocation_nadir[]/cor_coor_nad[] 

description 
cor_coor_nad[0] and cor_coor_nad[1] are taken from the first pixel and cor_coor_nad[2] and cor_coor_nad[3] are taken from the Nth pixel; corners are rearranged in the following way: 0,2,3,1 

condition 
Coadding needed of both forward and backward scan pixels (N is divisible by 5) 

path 
/geolocation_nadir[]/cor_coor_nad[] 

description 
cor_coor_nad[0] is taken from the first pixel, cor_coor_nad[2] is taken from the fourth pixel, cor_coor_nad[1] is taken from cor_coor_nad[3] of the Nth pixel, and cor_coor_nad[3] is taken from cor_coor_nad[1] from the Nth pixel; corners are rearranged in the following way: 0,2,3,1 

solar_zenith_angle 
condition 
No coadding needed 
path 
/geolocation_nadir[]/sol_zen_angle_toa[1] 

condition 
Coadding needed and all N geolocations are within a single scan (N is not divisible by 5) 

path 
/geolocation_nadir[]/sol_zen_angle_toa[2] 

description 
the value at end of integration time of the N/2th geolocation 

condition 
Coadding needed of both forward and backward scan pixels (N is divisible by 5) 

path 
/geolocation_nadir[]/sol_zen_angle_toa[1], /geolocation_nadir[]/sol_zen_angle_toa[2] 

description 
the average of the value at end of integration time of the second record and the value at middle of integration time of the Nth record 

viewing_zenith_angle 
condition 
No coadding needed 
path 
/geolocation_nadir[]/los_zen_angle_toa[1] 

condition 
Coadding needed and all N geolocations are within a single scan (N is not divisible by 5) 

path 
/geolocation_nadir[]/los_zen_angle_toa[2] 

description 
the value at end of integration time of the N/2th geolocation 

condition 
Coadding needed of both forward and backward scan pixels (N is divisible by 5) 

path 
/geolocation_nadir[]/los_zen_angle_toa[1], /geolocation_nadir[]/los_zen_angle_toa[2] 

description 
the average of the value at end of integration time of the second record and the value at middle of integration time of the Nth record 

relative_azimuth_angle 
condition 
No coadding needed 
path 
/geolocation_nadir[]/rel_azi_angle_toa[1] 

condition 
Coadding needed and all N geolocations are within a single scan (N is not divisible by 5) 

path 
/geolocation_nadir[]/rel_azi_angle_toa[2] 

description 
the value at end of integration time of the N/2th geolocation 

condition 
Coadding needed of both forward and backward scan pixels (N is divisible by 5) 

path 
/geolocation_nadir[]/rel_azi_angle_toa[1], /geolocation_nadir[]/rel_azi_angle_toa[2] 

description 
the average of the value at end of integration time of the second record and the value at middle of integration time of the Nth record 

scan_direction_type 
path 
/geolocation_nadir[]/corner_coord[], /geolocation_nadir[]/dsr_time 
description 
When the integration time is higher than 1s we are dealing with a mixed (2) pixel, otherwise the scan direction is based on the corner coordinates of the first ground pixel of the measurement. The first geolocation pixel is a backscan (1) pixel if the inproduct of the unit vector of the third corner with the outproduct of the unit vector of the first corner and the unit vector of the second corner is negative (otherwise it is part of a forward (0) scan) 

C2H2O2_column_number_density 
path 
/nad_uv9_chocho[]/vcd[0] 
C2H2O2_column_number_density_uncertainty 
path 
/nad_uv9_chocho[]/vcd_err[0], /nad_uv8_h2o[]/vcd[0] 
description 
relative error is converted to absolute error by multiplying with measured value 

C2H2O2_column_number_density_validity 
path 
/nad_uv9_chocho[]/flag_vcd_flags 
cloud_fraction 
path 
/clouds_aerosol[]/cl_frac 