# IASI_L1

## Variables

The table below lists the variables that are present in the HARP product that results from an ingestion of IASI_L1 data.

field name

type

dimensions

unit

description

datetime

double

{time}

[seconds since 2000-01-01]

time of the measurement

orbit_index

int32

absolute orbit number

latitude

double

{time}

[degree_north]

center latitude of the measurement

longitude

double

{time}

[degree_east]

center longitude of the measurement

float

{time, spectral}

[W/m^2.sr.m^-1]

wavenumber

float

{time, spectral}

[m^-1]

nominal wavelength assignment for each of the detector pixels

scan_subindex

int8

{time}

relative index (0-119) of this measurement within an MDR

index

int32

{time}

zero-based index of the sample within the source product

## Mapping description

IASI Level 1 products contain a number of scanlines, each scanline contains 30 scans, each scan contains 4 spectra and each spectrum contains 8700 measurements

The table below details where and how each variable was retrieved from the input product.

field name

mapping description

datetime

path

description

orbit_index

path

/MPHR/ORBIT_START

latitude

path

/MDR[]/MDR/GGeoSondLoc[,,1]

longitude

path

/MDR[]/MDR/GGeoSondLoc[,,0]

path

description

spectral data is scaled using the information in GIADR_ScaleFactors:for numScale = 0 to (IDefScaleSondNbScale - 1) do { SF = IDefScaleSondScaleFactor[numScale]; for chanNb = IdefScaleSondNsfirst[numScale] to IDefScaleSondNslast[numScale] do { w = chanNb - IDefNsfirst1b + 1; pixel_readout[w] = GS1cSpect[..,..,w] * 10^(-SF) } }

wavenumber

path

/MDR[]/MDR/IDefSpectDWn1b, /MDR[]/MDR/IDefNsfirst1b, /MDR[]/MDR/IDefNslast1b

description

wavenumber[i] = IDefSpectDWn1b * (i + IDefNsfirst1b - 1).