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Weather forecast to become more accurate as new technique found now

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Meteorologists have long known for wrong rainfall forecasts but now researchers from the University of Missouri have developed a system that improves the precision of forecasts by accounting for evaporation in rainfall estimates, particularly for locations 30 miles or more from the nearest National Weather Service radar.

“Right now, forecasts are generally not accounting for what happens to a raindrop after it is picked up by radar,” said Neil Fox of the School of Natural Resources at MU. “Evaporation has a substantial impact on the amount of rainfall that actually reaches the ground. By measuring that impact, we can produce more accurate forecasts that give farmers, agriculture specialists and the public the information they need.”

Fox and doctoral student Quinn Pallardy used dual-polarization radar, which sends out two radar beams polarized horizontally and vertically, to differentiate between the sizes of raindrops. Since the size of a raindrop affects both its evaporation rate and its motion, with smaller raindrops evaporating more quickly but encountering less air resistance, a combination technique has helped them make the prediction more accurate.

By combining this information with a model that assessed the humidity of the atmosphere, the researchers were able to develop a tracing method that followed raindrops from the point when they were observed by the radar to when they hit the ground, precisely determining how much evaporation would occur for any given raindrop.

Researchers found that this method significantly improved the accuracy of rainfall estimates, especially in locations at least 30 miles from the nearest National Weather Service radar. Radar beams rise higher into the atmosphere as they travel, and as a result, radar that does not account for evaporation becomes less accurate at greater distances because it observes raindrops that have not yet evaporated.

“Many of the areas that are further from the radar have a lot of agriculture,” Fox said. “Farmers depend on rainfall estimates to help them manage their crops, so the more accurate we can make forecasts, the more those forecasts can benefit the people who rely on them.”

Fox said more accurate rainfall estimates also contribute to better weather forecasts in general, as rainfall can affect storm behavior, air quality and a variety of other weather factors.

New Technique Developed to Detect Epilepsy Brain Region for Surgery

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Researchers have identified a unique way to detect epileptic brain tissue that causes seizures.

The chemical biomarker can be detected noninvasively using a technique called magnetic resonance spectroscopy to help doctors to precisely identify small regions of abnormal brain tissue in early-stage epilepsy patients. This can help in surgery of epileptic brain regions for therapeutic removal without the need for additional surgery, said researchers.

Epilepsy affects about one percent of people worldwide and it is characterized by unpredictable seizures that occur when groups of neurons in the brain abnormally fire in unison. About 30 percent of epilepsy patients don’t respond to drugs and surgery is only the option to remove areas of the brain associated with epileptic activity.

“One of the biggest challenges in epilepsy is in diagnosis,” said Dr. Jeffrey Loeb, John S. Garvin Chair and head of neurology and rehabilitation in the University of Illinois at Chicago College of Medicine and corresponding author on the study.

Current non-invasive techniques can’t detect epileptic areas of the brain smaller than approximately eight to 10 square centimeters, so many early-stage epilepsy patients often go undiagnosed and untreated.

“With this new biomarker, we should be able to detect very small regions of epileptic activity — smaller than a single square centimeter — and we do it noninvasively,” Loeb said.

The biomarker may soon make the need for surgery to identify epileptic regions of the brain for later removal obsolete. To locate these areas, surgeons implant electrodes across the surface of the brain that need to stay in place for many days.

Dr. Jeffrey Loeb, John S. Garvin Chair and head of neurology and rehabilitation in the UIC College of Medicine. CREDIT Jenny Fontaine, UIC

Loeb and colleagues used a technique called magnetic resonance spectroscopy to identify the metabolomic signature of epileptic versus non-epileptic brain tissues removed from nine patients who underwent invasive electrical brain monitoring as part of their epilepsy surgery. Magnetic resonance spectroscopy can detect compounds associated with cellular metabolism. As part of this therapeutic surgery, both epileptic and nearby regions with less or no epileptic electrical activity were also removed.

Loeb and colleagues scanned both types of tissue with a powerful 11.7 Tesla magnetic resonance spectroscopy machine at Wayne State University in Detroit. They found that tissue with high levels of epileptic electrical activity was low in lactate and had higher levels of creatine, phosphocreatine and choline, suggestive of abnormal metabolism.

When they looked at these tissues in the lab, they saw that it had increased vascularization compared to tissue with low or no epileptic electrical activity. Genetic analysis of the same tissue regions revealed higher activation of genes associated with vascularization and altered metabolic states.

“Previous studies have used magnetic resonance spectroscopy to look at single metabolites in epileptic brain tissue, but ours is the first to use high strength magnets to look at multiple metabolites simultaneously,” Loeb said. “When combined with our genomic and histological data from these same samples, the biomarker profile was not only highly specific for epileptic brain tissues, but also revealed an abnormal metabolic and vascular state that could underlie the epileptic condition.”

The reason behind the abnormal metabolic profile in epileptic tissue remains unknown and needs to be studied further, said Loeb. “These are areas of the brain where large populations of neurons are firing often, and this uses up a lot of energy, so it’s not surprising that we see an altered metabolic profile with a massive expansion of blood vessels.”

The findings are reported in the journal Epilepsia.