USA David M. Engle, along with other scientists at Oklahoma State University, are making a case that soil moisture should be used as one of the components in determining grassland fire danger ratings.
The percent of maximum soil moisture available to plants in the top 16 inches in Oklahoma, September 11, 2016.
To assess the herbaceous fuel dynamics in grasslands, they conducted 3 studies:
1) A study that used a database of large wildfires in Oklahoma to examine the relationship of fire occurrence and fire size with soil moisture;
2) An intensive field-based study to quantify and subsequently model herbaceous fuel load and moisture content in grassland patches that differed in time since fire and, therefore, proportion of live and dead herbaceous fuel load, and;
3) Modeling the influence of herbaceous fuel dynamics and weather conditions on fire behavior in tallgrass prairie.
Winters have started approaching the northern region of India that also includes Delhi-NCR along with Punjab and Haryana. Due to this, minimums have also started dropping in many parts of North India including Delhi and NCR. In fact, as per the temperatures recorded on October 15 and October 17, the minimums ofDelhi and NCR went down to 17°C.
As per experts, an increase in the pollution level normally occurs during the winter months. However, there are a few reasons that could enhance the pollution level in Delhi and the adjoining areas. The very first reason that can be attributed to an increase in pollution level in the national capital is crop fires in the neighboring state ofHaryana andPunjab.
These two states lie in northwest proximity of Delhi and normal pattern of winds during this season is northwesterly. These winds drag the smoke and fine particles of the burnt crop and mix them with Delhis atmosphere. Moreover, the temperatures also start dipping, therefore, the air near the earths surface tends to condense leading to formation of haze.
Whenever the winds are light or calm, these air pollutants get mixed with the haze or mist and forms a blanket of smoke haze which remains suspended for few hours in the mornings. Thereafter, the haze disappears as the sun rises and temperatures increases during the day.
But as the winter progresses in the month of December and January, the duration of haze, mist or fog gets extended and these pollutants remain suspended in the atmosphere for longer duration of time. Other factors including the smoke emitting from vehicles and factories and dust from construction sites also add to the rising pollution levels.
Sometimes this situation can continue for days altogether. However, relief is expected only when a strong Western Disturbance gives rain over the region. It is then that these pollutants settle down for a few days.
Another criterion which reduces the pollution levels is the strong and moderate dry winds from northwest or west which carry away these pollution particles. In a nutshell, it can be said that in October, intensity and duration of pollution remain less though increases in November as winters sets in.
– See more at: http://www.skymetweather.com/content/weather-news-and-analysis/delhis-pollution-level-increases-as-winter-approaches/#sthash.FRlJsEib.dpuf