NASA MODIS: Agricultural fires across Sierra Leone

Credit: NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team.

Marked in red, hundreds of land use fires burn in the fields across Sierra Leone.

Most fires in this region are deliberately set for a variety of reasons, including slash and burn agriculture.

When a plot of land becomes exhausted, farmers shift cultivation to another plot where they cut the trees and brush at the beginning of the dry season in January and February.

Once the dead plant material has dried, they set fire to it. Such fires peak in March and April right before farming season begins.

From space, MODIS detects thermal anomalies, including fires, flares, and volcanoes.

Each MODIS "fire pixel" or fire detection covers one square kilometer, which means that one or more fire is burning in the corresponding one-square kilometer area on the ground.

There are hundreds of fire pixels evident in this image, so there are at least that many distinct fires burning in this scene.

MODIS tends to undercount fires because it can't detect fires through smoke or clouds, nor does it see small cool fires, a fire type common to land use fires.

Where there is fire, there is also smoke, affecting air quality. Smoke contains soot and other particulates that pose a threat to human health and affect regional climate. Burning also releases greenhouse gases.

This natural-colour satellite image was collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite on March 24, 2014.

Japan to launch satellites to monitor oceans against piracy and encroachment

The Senkaku islands, known as Diaoyu by aggressive China.

Japan plans to launch Earth Observation (EO) satellites to monitor the world's oceans as the aggressive Chinese government ships sailed into waters around islands controlled by Tokyo.

The Japanese Cabinet office plans to launch nine EO satellites in the next five years to counter piracy and monitor the movements of foreign ships intruding into Japanese territorial waters.

They will also collect data for forecasting natural disasters such as tsunamis and tropical storms.

The report, which cabinet officials could not immediately confirm, came as Japan's coastguard said three Chinese government ships entered waters around the Senkaku islands in the East China Sea.

The maritime surveillance vessels entered the 12-nautical-mile zone around Uotsurijima, one of the Senkaku islands which oppressive China calls the Diaoyus, at about 9:30 am (0030 GMT), the Japanese coastguard reported.

The ships left the area shortly before 1:00 pm, according to an update by the coastguard.

Ships from the two countries have for months traded warnings over intrusions into what each regard as their territory, as Beijing and Tokyo jostle over political claims of ownership of the islands.

The territorial row that dates back four decades reignited last September when Tokyo nationalised three islands in the chain, in what it said was a mere administrative change of ownership.

Former Japanese prime minister Yukio Hatoyama came under fire in June after he said he understood China's aggressive claim to the islands.