Friday, January 6, 2017

Trend of Fires Over Northern India and Pakistan During The Last Decade 

The monsoon season (July – September) is the time when good rains aid rice cultivation in the northern states of India. Monsoon starts receding from North India in the beginning of October. Rice is harvested and then during October-November the crop-residue is burnt to clear the agricultural land and prepare it for the next crop. Fires set for clearing large portions of land results in huge amounts of smoke (or PM2.5) that gets transported to the Indo-Gangetic Basin (IGB) by north westerly winds. Air quality deteriorates significantly in the entire IGB region.

Smoke over IGB can be clearly seen in true color (RGB) satellite image (Figure 1) from October 30, 2016 taken over Northern India by VIIRS instrument. The red dots in the image are the fire locations, most of which are in the state of Punjab. Smoke transported over north indian states can be easily seen in the image. Mapping of all the fires observed by the MODIS satellite instrument (Figure 2) shows that majority of the fires during October 1 - November 18, 2016 are located in Punjab (see orange dots).

The number of fires over northern India and adjacent Pakistan region [23-35 N ; 70 - 85 E) during Oct-Nov months (Figure 3), as detected by MODIS between 2005 and 2016, shows some interesting features.  The total number of fires during the two months show some variability from year to year but there is no clear trend of increase or decrease in the number of fires. Fire count during 2016 are definitely higher than 2015. Note that 2016 fire count data are preliminary and only upto 18 Nov, 2016. More interesting is the shift in the crop residue burning month.  From 2005 to 2011 (barring 2010), the number of fires in October exceeded those in November. There is a substantial difference in October vs November fire counts between 2005-2008 ; the differences reduce thereafter. From 2012 to 2016, the number of fires during October are less than fires in November; with fire count differences increasing between the two months.

Increased fire activity points towards deteriorating air quality conditions that adversely impact human health conditions. The shifting pattern in the burning season, on the other hand, is an indicator of a shift in regional climatic conditions and perhaps the growing and monsoon season itself.

Thursday, August 11, 2016

Fire, smoke and air quality in Portugal

Series of images taken by NOAA’s NPP VIIRS satellite over Portugal and northern Spain showing progression of fires in the region. There were no fires on August 5th. Small fires (red dots on the image) started appearing on August 6th and quickly spreading all over the region. In general this region observe good air quality conditions with observed AODs on August 5th are less than 0.1. As fire started spreading in the larger region, air quality quickly became poor with AOD values as high as 1.0 (even higher in some areas). The impact on air quality over populated area still remains minimal due to prevailing wind directions, which transported most of the smoke over ocean. Read more on these fires at BBC

Saturday, August 6, 2016

Fires and smoke continue in central Russia: Satellite View

Fires in central Russia are burning for almost two months now. These satellite images from August 4, 2016 show fire, smoke and its impact on atmospheric aerosol loading and air quality in the region. The Aerosol Optical Depth (AOD) is a measure of particle loading in the atmosphere, which reaches as high as 2-3 on this day, which indicates very high loading of PM2.5 in the air. Another air quality indicator and emission from fires is carbon monoxide (CO) gas showing very high concentration in the satellite image. Data source: NASA Worldview (

Saturday, April 30, 2016

Forest in Uttarakhand Burning for Months: A Satellite View

Forests in Uttarakhand region of India are burning for months. Since February, these fires have destroyed thousands of hectares of forest. Dry conditions combined with high temperature and strong winds have facilitated the fires to spread in the entire region (Travel India).

Smoke from the fires have filled the entire valley and spreading in surrounding regions, reaching to Delhi and other highly populated areas. This is a huge concern for the rising air pollution level in the region. Air Quality in many urban and rural area has been reached to a hazardous level.

Following Image shows the fires detected by NASA VIIRS sensor on NPP satellite on March 28th (top) and April 28th (bottom). The number of fires has drastically increased over the time.

The following series of images shows how smoke is spreading in the different region over the time. Images are taken by NASA’s MODIS TERRA Satellite.

The following image shows aerosol optical depth (a proxy for PM2.5) on April 30th over Indian region. The blue is for low and red is for high aerosol loading.

All the images were created using NASA Worldview

Sunday, January 31, 2016

NASA Images Show Dump Fires in Mumbai: Wind is making it worst

Deonar dump fire in Mumbai that started sometime on January 27-28 still putting out smoke and making air toxic for breathing. The different part of the city has been experiencing smog and hazardous air quality. The change in the wind direction spreading the smoke for fires in different part of the city. NASA/NOAA satellite VIIRS images (top panels) from Jan 27-31, 2016 clearly show a wide spread of smoke from this fires. NASA’s high-resolution satellite LANDSAT on January 28, 2016, also capture the fires and smoke (bottom panel).