Monitoring light patterns: Can Satellite images reveal the impact of the Syrian conflict?

TRES 35-18 Syrian night-light fig.1

An interesting new paper recently published in the International Journal of Remote Sensing which hypothesises that night-time light can be a useful source for monitoring humanitarian crises, such as that unfolding in Syria.

The ongoing Syrian Crisis, which broke out in April 2011, has been a severe humanitarian disaster, with more than 190,000 deaths since the start of the conflict.

However, evaluating the ongoing crisis in Syria is challenging, because reliable and comprehensive witness reports are hard to gather in a war zone.

Therefore, satellite images, as one of the few sources of objective information, are potentially of great importance.

Deren Li Wuhan University

In their recent study published in International Journal of Remote Sensing, Xi Li and Deren Li analysed the effect of the Syrian Crisis on levels of night-time light as a means of evaluating and monitoring the conflict.

By comparing the levels of light in March 2011 and February 2014, (see Fig 1. attached) they found that in all of the provinces, the levels of night-time light had declined sharply following the breakout of the conflict.

Indeed, in most provinces, the level of night-time light decreased by more than 60%.

Notably, the authors also found that the number of internally displaced persons (IDPs) from each province showed a linear correlation with the level of night-light loss.

This relationship between the number of displaced persons and the drop in night-time light levels may allow for the quantitative estimation of the number of IDPs from other areas of conflict, such as Iraq, where the activities of Islamic State are causing significant civil unrest.

More information: "Can night-time light images play a role in evaluating the Syrian Crisis?", by Xi Li and Deren Li, International Journal of Remote Sensing, Volume 35, Issue 18, pages 6648-6661, 2014, published by Taylor & Francis Group. dx.doi.org/10.1080/01431161.2014.971469

Did Comet attacks end 9,000-year-old Clovis culture?

Sandia National Laboratories' Mark Boslough rebuts a speculative hypothesis about comets leading to the end of the Clovis culture in North America. Photo by Randy Montoya.

Sandia lead author Mark Boslough rebuts a speculative hypothesis that comet explosions changed Earth's climate sufficiently to end the Clovis culture in North America about 13,000 years ago.

He and other researchers from 14 academic institutions assert that some other, more plausible, explanations must be found for the apparent disappearance.

"There's no plausible mechanism to get airbursts over an entire continent," said Boslough, a physicist. "For this and other reasons, we conclude that the impact hypothesis is, unfortunately, bogus."

In a December 2012 American Geophysical Union (AGU) monograph, first available in January, the researchers point out that no appropriately sized impact craters from that time period have been discovered, nor have any unambiguously "shocked" materials been found.

In addition, proposed fragmentation and explosion mechanisms "do not conserve energy or momentum," a basic law of physics that must be satisfied for impact-caused climate change to have validity, the authors write.

Also absent are physics-based models that support the impact hypothesis. Models that do exist, write the authors, contradict the asteroid-impact hypothesis.

The authors also charge that "several independent researchers have been unable to reproduce reported results" and that samples presented in support of the asteroid impact hypothesis were later discovered by carbon dating to be contaminated with modern material.

NB: Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear Security Administration.