Remote sensing and GIS in Agrometeorology
Remote Sensing: The science of collecting data about an object or area from a distance using sensors (satellites, aircraft, drones).
Types of Remote Sensing
- Active Remote Sensing: emits its own energy (e.g., RADAR, LiDAR).
- Passive Remote Sensing: detects reflected solar radiation (e.g., Landsat, NOAA).
GIS (Geographical Information System)
- A computer-based tool for mapping, analyzing, and managing spatial data.
- Integrates soil, weather, and crop data for better decision-making.
Important Indian Remote Sensing Satellites
|
Satellite |
Year |
Application |
|
IRS-1A |
1988 |
Land use mapping |
|
IRS-P4 (Oceansat) |
1999 |
Ocean parameters |
|
Resourcesat-1 |
2003 |
Agricultural monitoring |
|
Cartosat series |
2005 onwards |
High-resolution mapping |
|
INSAT series |
1983 onwards |
Meteorological observations |
Agrometeorological models
Definition: Mathematical or computer-based models that simulate crop growth, yield, and weather interactions under varying environmental conditions.
Types of Models
- Empirical Models: Based on statistical relationships (e.g., regression models).
- Simulation Models: Based on physical and physiological processes of crop growth.
Popular Crop Simulation Models
|
Model |
Developer |
Application |
|
DSSAT (Decision Support System for Agrotechnology Transfer) |
USA |
Predicts yield, growth, and soil moisture. |
|
WOFOST (World Food Studies Model) |
Netherlands |
Simulates crop growth under varying conditions. |
|
INFOCROP |
ICAR (India) |
Used for Indian crop systems and climate change analysis. |
|
APSIM (Agricultural Production Systems Simulator) |
Australia |
Simulates cropping systems and management practices. |
|
CERES (Crop Environment Resource Synthesis) |
DSSAT family |
For wheat, rice, and maize growth simulation. |
Meteorological units and conversions
|
Parameter |
Unit |
Conversion |
|
Temperature |
°C, K |
K = °C + 273 |
|
Pressure |
millibar (mb), hectopascal (hPa) |
1 mb = 1 hPa |
|
Wind speed |
m/s or km/hr |
1 m/s = 3.6 km/hr |
|
Rainfall |
millimeter (mm) |
1 mm = 1 litre/m² |
|
Energy (Radiation) |
cal/cm²/day, W/m² |
1 cal/cm²/min = 697.4 W/m² |
|
Evaporation |
mm/day |
– |
|
Relative humidity |
% |
(Actual Vapour Pressure / Saturation Vapour Pressure) × 100 |
Wind and Pressure Systems
- Wind: Horizontal movement of air from high to low pressure.
- Measured using Anemometer (speed) and Wind Vane (direction).
- Types of Winds:
- Planetary winds – trade, westerlies, polar easterlies
- Periodic winds – monsoon
- Local winds – land and sea breeze, loo, mistral
Fact: Coriolis Force deflects winds — to the right in the Northern Hemisphere and left in the Southern Hemisphere.
Weather Forecasting in Agriculture
- Types:
-
- Nowcasting – up to 24 hrs
- Short-range forecast – 1–3 days
- Medium-range forecast – 3–10 days
- Long-range forecast – 10 days–3 months
- Agro-Advisory Services (AAS): Provided by IMD (Indian Meteorological Department) through District Agro-Meteorological Units (DAMUs).
Fact:
- IMD established in 1875.
- Headquarter: New Delhi.
- Mausam App provides real-time weather updates.
Seasonal Classification (IMD)
|
Season |
Period |
Major Features |
|
Winter |
Jan–Feb |
Cool, dry |
|
Pre-Monsoon (Summer) |
Mar–May |
Hot, dry, thunderstorms |
|
South-West Monsoon |
Jun–Sep |
Heavy rainfall |
|
Post-Monsoon (N-E Monsoon) |
Oct–Dec |
Retreating rains |
Fact File: Monsoon and Rainfall
- Average annual rainfall of India: ~118 cm
- Wettest place on Earth: Mawsynram (~11,872 mm)
- Driest place: Leh (Ladakh) – less than 10 cm/year
- Rain shadow regions: Interior Deccan Plateau, parts of Karnataka and Tamil Nadu
- Rainfall in India:
- 60% from SW Monsoon
- 25% from NE Monsoon
- 15% from cyclonic storms and local showers
