Q. 1
Atmospheric Sciences
Difficulty: Easy
(1 Mark)
What is the Normalized Difference Vegetation Index (NDVI) formula used in satellite environmental monitoring?
💡
Step-by-Step Explanation & Concept Rationale
NDVI = (NIR - Red) / (NIR + Red) exploits the strong absorption of red light by chlorophyll and high reflectance of near-infrared (NIR) radiation by healthy leaf mesophyll structure.
Q. 2
Atmospheric Sciences
Difficulty: Medium
(1 Mark)
What is 'Aerosol Optical Depth' (AOD) retrieved by spaceborne sensors like MODIS and MISR?
💡
Step-by-Step Explanation & Concept Rationale
AOD is a dimensionless measure of solar beam attenuation by aerosols: values > 0.5 to 1.0 indicate hazy conditions or heavy smog, frequently observed over Punjab during winter.
Q. 3
Atmospheric Sciences
Difficulty: Easy
(1 Mark)
Which satellite sensor system operated by NASA on Terra and Aqua satellites provides daily global coverage of fires, aerosols, snow cover, and sea surface temperature?
💡
Step-by-Step Explanation & Concept Rationale
MODIS on NASA's Terra and Aqua satellites views Earth in 36 spectral bands, providing essential environmental data for climate, forestry, and weather models.
Q. 4
Atmospheric Sciences
Difficulty: Medium
(1 Mark)
In satellite remote sensing, what is a 'Sun-Synchronous Orbit'?
💡
Step-by-Step Explanation & Concept Rationale
Sun-synchronous polar orbits (~700-800 km altitude, inclination ~98°) precess eastward at ~1° per day to match Earth's orbital movement around the sun, keeping solar angles constant.
Q. 5
Atmospheric Sciences
Difficulty: Easy
(1 Mark)
What is 'Spatial Resolution' in satellite earth observation?
💡
Step-by-Step Explanation & Concept Rationale
Spatial resolution refers to the smallest ground footprint distinguishable as an individual pixel on the sensor's detector array.
Q. 6
Atmospheric Sciences
Difficulty: Easy
(1 Mark)
What is 'Temporal Resolution' of an earth-observing satellite system?
💡
Step-by-Step Explanation & Concept Rationale
Temporal resolution is the repeat cycle or revisit time of a satellite system (e.g., 15 minutes for geostationary, 16 days for Landsat, 5 days for Sentinel-2).
Q. 7
Atmospheric Sciences
Difficulty: Medium
(1 Mark)
What is 'Spectral Resolution' in optical remote sensing?
💡
Step-by-Step Explanation & Concept Rationale
Spectral resolution describes the specific electromagnetic wavelength intervals measured by the sensor (panchromatic vs multispectral vs hyperspectral with hundreds of contiguous narrow bands).
Q. 8
Atmospheric Sciences
Difficulty: Hard
(1 Mark)
What is the 'Normalized Difference Snow Index' (NDSI) used for in mountain snowpack monitoring?
💡
Step-by-Step Explanation & Concept Rationale
NDSI exploits the optical property that snow has high reflectance in visible wavelengths (green) but strong absorption in the 1.6 micrometer SWIR band, whereas water clouds remain highly reflective in both.
Q. 9
Atmospheric Sciences
Difficulty: Medium
(1 Mark)
What is 'Synthetic Aperture Radar' (SAR) and why is it invaluable for flood and landslide monitoring in Pakistan?
💡
Step-by-Step Explanation & Concept Rationale
SAR (such as Sentinel-1) emits microwave pulses that penetrate clouds, heavy rain, and work day or night. Smooth floodwater specularly reflects radar pulses away, appearing distinctively black.
Q. 10
Atmospheric Sciences
Difficulty: Hard
(1 Mark)
What is 'Interferometric Synthetic Aperture Radar' (InSAR)?
💡
Step-by-Step Explanation & Concept Rationale
InSAR exploits electromagnetic wave phase differences across repeat passes to map surface deformation, fault movements, tectonic subsidence, and landslide movements with millimeter precision.
Q. 11
Atmospheric Sciences
Difficulty: Easy
(1 Mark)
What satellite constellation operated by the European Union's Copernicus Programme provides free open-access multispectral imagery (10 m resolution) and C-band SAR radar imagery?
💡
Step-by-Step Explanation & Concept Rationale
The European Copernicus Sentinel missions (Sentinel-1 radar, Sentinel-2 optical, Sentinel-5P atmospheric chemistry) provide standard global environmental monitoring data.
Q. 12
Atmospheric Sciences
Difficulty: Hard
(1 Mark)
What is the 'Atmospheric Correction' of satellite optical imagery?
💡
Step-by-Step Explanation & Concept Rationale
Atmospheric correction algorithms model and eliminate Rayleigh scattering, aerosol backscatter, and ozone/water vapor absorption to yield bottom-of-atmosphere (BOA) surface reflectance.
Q. 13
Atmospheric Sciences
Difficulty: Medium
(1 Mark)
What spaceborne radar mission launched jointly by NASA and JAXA revolutionized tropical precipitation measurement using Ku/Ka-band dual-frequency precipitation radar?
💡
Step-by-Step Explanation & Concept Rationale
The GPM Core Observatory (launched 2014, building on the Tropical Rainfall Measuring Mission TRMM) carries the Dual-frequency Precipitation Radar (DPR) to profile rain and snow globally.
Q. 14
Atmospheric Sciences
Difficulty: Medium
(1 Mark)
What instrument onboard the Sentinel-5P satellite provides daily global maps of atmospheric pollutants such as NO2, SO2, CO, methane, and aerosol index?
💡
Step-by-Step Explanation & Concept Rationale
TROPOMI on Sentinel-5 Precursor provides high-resolution (approx 5.5 x 3.5 km) daily mapping of tropospheric trace gases, tracking urban smog plumes over cities like Lahore and Karachi.
Q. 15
Atmospheric Sciences
Difficulty: Easy
(1 Mark)
What is 'Digital Elevation Model' (DEM) in GIS, critical for hydrological modeling and flood inundation simulation?
💡
Step-by-Step Explanation & Concept Rationale
A DEM (such as SRTM or ALOS World 3D) represents ground surface topography as a raster grid of elevation values, essential for watershed delineation, flow routing, and flood simulations.
Study Stream Progress:
Showing 15 of 15 Questions (100%)
Ready to Test Your Retention & Speed?
Now that you have reviewed the study questions and rationales, test yourself in our interactive 1-by-1 practice engine or take the full official timed mock exam.