WMO OSCAR | Details for Instrument VHRR (INSAT)

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Instrument: VHRR (INSAT)

Instrument details

Acronym	VHRR (INSAT)
Full name	Very High Resolution Radiometer
Purpose	Multi-purpose imagery and wind derivation by tracking clouds and water vapour features
Short description	3 VIS/TIR channels [see detailed characteristics below]
Background	Heritage of VHRR flown on ATS-6
Scanning Technique	Mechanical, 3-axis stabilised satellite, E-W continuous, S-N stepping
Resolution	8.0 km for IR channels; 2 km for the VIS channel
Coverage / Cycle	Full disk every 3 hours for INSAT-2E, 1 hour for INSAT-3A (with half-hourly triplets around 00 and 12 UT for winds), half-hour for Kalpana-1
Mass	60 kg	Power	37 W	Data Rate	530 kbps

Providing Agency	ISRO
Instrument Maturity	Flown on operational programme
Utilization Period:	1982 to 2017
Last update:	2021-10-18

Detailed characteristics

Central wavelength	Spectral interval	SNR or NEΔT @ specified input
0.65 µm	0.55 - 0.75 µm	6 @ 2.5 % albedo
6.40 µm	5.70 - 7.10 µm	0.5 K @ 300 K
11.5 µm	10.5 - 12.5 µm	0.25 K @ 300 K

Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Indian National Satellite - 1 (ISRO)
- INSAT-1A (see instrument status) Jul 1982 - Sep 1982
- INSAT-1B (see instrument status) Nov 1983 - Jul 1993
- INSAT-1C (see instrument status) Oct 1988 - Nov 1989
- INSAT-1D (see instrument status) Sep 1990 - May 2002
Indian National Satellite - 2 (ISRO)
- INSAT-2A (see instrument status) Oct 1992 - May 2002
- INSAT-2B (see instrument status) Oct 1993 - Jul 2004
- INSAT-2D (see instrument status) Sep 1997 - Oct 1997
- INSAT-2E (see instrument status) Jul 1999 - Apr 2012
Indian National Satellite - 3 (IMD)
- INSAT-3A (see instrument status) Jul 2003 - Sep 2016
Kalpana (ISRO)
- Kalpana-1 (see instrument status) Dec 2002 - Sep 2017

Instrument classification

Earth observation instrument
Passive optical radiometer or spectrometer
Moderate resolution optical imager

WIGOS Subcomponents

Subcomponent 1
Multi-spectral VIS/IR imagery With rapid repeat cycles [in GEO]
Multi-spectral VIS/IR imager with rapid repeat cycles [in GEO]

Mission objectives

Primary mission objectives

Cloud cover
Cloud top height
Cloud top temperature
Cloud type
Integrated Water Vapour (IWV)
Wind (horizontal)

Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.

Variable	Relevance for measuring this variable	Operational limitations	Explanation
Accumulated precipitation	4 - fair	Convective precipitation dominant.. Calibration by MW needed.	TIR channel(s) in the 10-13 micrometers range. Frequent sampling (GEO) is essential for accumulated precipitation.
Cloud cover*	4 - fair	No specific limitation.	VIS and TIR channels
Cloud top height*	3 - high	No specific limitation.	TIR channels in window and water vapour band (for emissivity) to estimate cloud top height from its temperature
Cloud top temperature*	3 - high	No specific limitation.	TIR channels in window and water vapour band (for emissivity)
Cloud type*	4 - fair	Daylight only.	VIS and TIR channels
Fire fractional cover	4 - fair	Cloud sensitive.. Coarse spatial resolution.	VIS and TIR channels
Fire radiative power	5 - marginal	Cloud sensitive.. Coarse spatial resolution.	TIR channels. Frequent sampling (GEO) enables early detection
Fire temperature	5 - marginal	Cloud sensitive.. Coarse spatial resolution.	TIR channels. Frequent sampling (GEO) enables early detection
Precipitation intensity at surface (liquid or solid)	3 - high	Convective precipitation dominant.. Calibration by MW needed.	TIR channel(s) in the 11 micrometers window. Frequent sampling (GEO) consistent with precipitation temporal variability
Sea surface temperature	5 - marginal	Cloud sensitive.	TIR window channel(s) around 11 micrometers .
Snow cover	5 - marginal	Cloud sensitive.. Daylight only.	VIS channel(s). Frequent sampling (GEO) improves probability of cloud-free views
Soil moisture at surface	4 - fair	Cloud sensitive.. Index only.	VIS and TIR window channels. Soil moisture inferred from thermal inertia, that is accurately measured by frequent sampling (GEO)
Integrated Water Vapour (IWV)*	4 - fair	Cloud sensitive.. Middle troposphere dominant.	TIR channels in the water vapour band around 6.3 micrometers
Aerosol volcanic ash Total Column	1 - primary	Cloud sensitive.	TIR channel(s). Frequent sampling (GEO) enables early detection of ash plumes
Wind (horizontal)*	3 - high	Cloud or water vapour tracers needed.	VIS channel(s) and TIR channels around 6.3 and 11 micrometers. Frequent sampling (GEO) enables inference from cloud or water vapour pathces motion