Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Raindrop Research Dials in Satellite Forecasting Accuracy

04.02.2014
Dialing in the accuracy of satellite weather forecasting is the goal behind basic research into raindrop size and shape being done at The University of Alabama in Huntsville by a UAH doctoral student who is also an atmospheric scientist in the NASA Pathways Intern Employment Program.

Patrick Gatlin says his work measuring the height and width of raindrops using ground instruments provides an accuracy baseline that is then scaled up to ground radar and then to satellite measurements.

He is co-author of a paper on the topic (Tokay, Ali, Walter A. Petersen, Patrick Gatlin, Matthew Wingo, 2013: Comparison of Raindrop Size Distribution Measurements by Collocated Disdrometers. J. Atmos. Oceanic Technol., 30, 1672–1690; http://dx.doi.org/10.1175/JTECH-D-12-00163.1).

“That’s really the whole purpose of measuring raindrops, is for remote sensing purposes,” Gatlin says. Scaling up accuracy from a small sensor on the ground to large sections of the Earth being observed from space requires very accurately calibrated instruments. “Our ability to correctly depict rainfall using a sensor in space is closely tied to knowing how precipitation varies, right down to the individual raindrop and snowflake size.”

Perfecting ground-level instrument observations, enlarging those to encompass ground-based radar and then going even larger to develop accurate satellite measuring instruments is the best way to reduce error as the area under observation increases. “Before we invest in all this satellite instrumentation,” Gatlin says, “let’s make sure we’ve got it right.”

A coming big step in scaling up precipitation forecasting is NASA’s planned launch of its Global Precipitation Measurement (GPM) satellite toward the end of February. UAH is a mission contractor, headed at the university by Dr. Larry Carey, an associate professor of atmospheric science, and involving UAH Earth System Science Center research scientist Matt Wingo, who is working with NASA at their flight facility in Wallops Island, Va.

“UAH designed the platform for some of the ground-based instruments that will validate the information from the satellite,” says Gatlin.

Carrying an advanced radar/radiometer system to measure precipitation from space, the GPM is the core of what will be a global network of measuring satellites that will provide next-generation global observations of rain and snow. It will serve as a reference standard to unify precipitation measurements from a constellation of research and operational satellites.

Through improved measurements of precipitation globally, the GPM mission will help to advance understanding of Earth's water and energy cycle, improve forecasting of extreme events that cause natural hazards and disasters, and extend current capabilities in using accurate and timely precipitation information.

In his own research, Gatlin has ranged from Iowa and Oklahoma to Canada, Finland, Italy and France. Rather than raindrops, the Canadian research was designed to collect snowflake images in order to improve the accuracy of measuring devices for snowfall.

In each locale, an integrated network of ground-level measuring devices have been deployed, like the Parsivel2, a disdrometer that measures the particle size and velocity of raindrops falling through a laser. Also in use are two-dimensional video disdrometers, which use two video angles to create 2-D pictures that enable determination of raindrop shapes. A video disdrometer on loan from frequent research collaborator Colorado State University is located on the UAH campus behind Cramer Hall.

During a field study, the instruments on the ground take measurements while a plane flies through the clouds to collect actual raindrop information and another flies high above the clouds with remote sensing equipment to mimic satellite radar detection. Results from all the measurement methods are compared.

Enhanced satellite-based precipitation measurements will improve both rainfall and snowfall predictions on a global scale, Gatlin says. “We’ll be measuring rain and snow in some areas where we’ve never measured it before.” The ability to better measure raindrop size also can have impact on severe weather forecasting, as small raindrops lead to higher evaporation rates that have been correlated with larger and more forceful microbursts by UAH’s Dr. Kevin Knupp and others.

Gatlin is about to finish up a global study focusing just on very large raindrops 5 millimeters in size and larger. These drops are difficult to capture in the small measuring area afforded by measuring instruments, and so their observation is rare. Gatlin says out of 224 million drops he has researched, only 8,000 have been 5 mm or larger.

“Even though large raindrops can have the greatest impact on radar measurements, we don’t have a good idea of their concentration,” he says. “What I’ve been doing is bringing together all the raindrop data bases that have collected various types of rainfall data using the same techniques.”

Interestingly, while Sumatra holds the honor of having the greatest number of large drops overall, the largest drop collected in his study fell through a measuring device at the UAH campus. It measured 9.1 mm and was formed in a hailstorm when a falling piece of hail melted before landing.

Patrick Gatlin | Newswise
Further information:
http://www.uah.edu

More articles from Earth Sciences:

nachricht Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University

nachricht NASA finds strongest storms in weakening Tropical Cyclone Sanba
15.02.2018 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

New printing technique uses cells and molecules to recreate biological structures

20.02.2018 | Life Sciences

New tech for commercial Lithium-ion batteries finds they can be charged 5 times fast

20.02.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>