Current Status of INSAT Meteorological Satellites Dr.V.Rajeswara Rao Scientist-E (Operations) Satellite Meteorology Division India Meteorological Department.

Current Status of INSAT Meteorological Satellites

Dr.V.Rajeswara RaoScientist-E (Operations)

Satellite Meteorology Division India Meteorological Department New Delhi, INDIA

Introduction

INSAT (Indian National Satellite) Program was started in late seventies to provide services to Meteorology, Telecommunication & Television Broadcast

All INSAT Satellites are geostationary, multi-purpose (except KALPANA-1)and 3-axis stabilized systems.

All these satellite are controlled and monitored by Master Control Facility (MCF), ISRO situated at Hassan, near Bangalore, India.

The first satellite INSAT-1A was launched on 10th April, 1982.

The India Meteorological Department processed the first earth image transmitted by INSAT-1A successfully with the ground reception system installed at IMD Head Quarter, New Delhi. Since then India Meteorological Department is involvedin receiving and processing data from INSAT-1, INSAT-2 and INSAT-3 series of satellites and different products generated and used for forecasting purposes.

Current Status of INSAT Meteorological Satellites

Currently there are two INSAT satellites in operation KALPANA-1

INSAT-3A KALPANA-1 is an exclusive meteorological satellite launched in September, 2002 and positioned at 74ºE by PSLV-C4 from India.

Originally named METSAT-1. Renamed as KALPANA-1 after Kalpana Chawla who perished in the space shuttle Columbia.

KALPANA-1 is currently working in inclined orbit with an inclination of 1.5 deg

INSAT-3A is a multi purpose satellite launched in April 2003 and positioned at 93.5ºE by European Ariane.

Both the satellite will transmit the VHRR data at the rate 526kbps

KALPANA-1 Payloads

It has two payloads for Meteorological Purposes

1. Very High Resolution Radiometer (VHRR) 2. Data Relay Transponder (DRT).

S.No

Payload Channel Spectral Bandwidth

Resolution

1. VHRR Visible 0.55 - 0.75 µm 2 Km. x 2 Km.

Infrared 10.5 - 12.5 µm 8 Km. x 8 Km.

WaterVapour

5.7 - 7.1 µm 8 Km. x 8 Km.

Characteristics of VHRR

DRT is used to transmit and receive data from AutomaticWeather Stations (AWS)

Modes of Operations

There are three Modes of Operation for VHRR payload.

1. Full Frame Mode 2. Normal Frame Mode3. Sector Scan Mode

The scan coverage in East-West is 20deg in all modeswhere as North-South coverage will vary depending uponthe mode..

The full frame mode is 20deg in both N-S and E-W direction and takes 33 minutes and number of lines will be 1560.

The normal mode covers a range of 14deg in N-S direction and 20deg in E-W direction and takes 23 minutes and number of lines will be 1092.

The sector scan mode which is useful for tracking the synoptic systems like thunderstorms etc. covers a range of 4.5 deg in N-S direction ( selectable) and 20deg in E-W direction takes 7minutes ( 3 scans in 23 minutes) and number of lines will be 351.

Presently this satellite is providing half hourly normal scans round the clock.

Normal Mode Scans KALPANA-1

Visible

Infrared

Water vapour

INSAT-3A Payloads

It has three payloads for Meteorological Purposes

1. Very High Resolution Radiometer (VHRR)2. Charged Coupled Device (CCD) 3. Data Relay Transponder (DRT).

S.No

Payload Channel Spectral Bandwidth

Resolution

1. VHRR Visible 0.55 - 0.75 µm 2 Km. x 2 Km.

Infrared 10.5 - 12.5 µm 8 Km. x 8 Km.

WaterVapour

5.7 - 7.1 µm 8 Km. x 8 Km.

INSAT-3A DRT is currently in use to transmit and receive data from Automatic Weather Stations (AWS)

The characteristics & modes of Operations of INSAT-3A VHRR Payload are exactly similar to KALPANA-1

Full Frame Mode Scans

INSAT-3A

Visible

Infrared

Water Vapour

Channels Spectral Range Resolution

Visible 0.63 - 0.69 µm 1 Km.

NIR 0.77 - 0.86 µm 1 Km.

SWIR 1.55 - 1.69 µm 1 Km.

INSAT-3A CCD Payload

Modes of Operation for CCD payload

There are two Modes of Operation for CCD payload. 1. Normal Mode 2. Program mode

The coverage in the normal mode will be 10 deg. Both in East-West and North-South directions

where as in the Program mode 1 to 25 lines, each covering 0.395 deg. In the North-South direction and 10deg. In East-West direction.

Currently IMD is processing hourly images during day time only.

Images from INSAT-3A CCD

Visible Near Infrared

Cyclone GIRI (CCD)Cyclone GIRI (K1)

Cyclone JAL (K1) Cyclone JAL (CCD)

Derivation of Geo Physical Parameters

Using the imagery data of these two satellites, IMD is also deriving the following geo physical parameters routinely.

Atmospheric Motion Vectors (AMV) Outgoing Longwave Radiation (OLR)Quantitative Precipitation Estimate (QPE) Sea Surface Temperature (SST)Upper Tropospheric Humidity (UTH)Normalised Difference Vegetation Index (NDVI)Aerosol Optical Depth (AOD)

INSAT-3D

Exclusive Meteorological Satellite

Launch Schedule: 2011

Three Payloads

1. 6-channel Imager2. 19-channel Sounder3. Data Relay Transponder