Nav: Home

Forecasting strong precipitation -- the potential of potential deformation

June 18, 2017

Vorticity, divergence and deformation are the three basic characteristics of wind fields. While many previous studies have revealed and confirmed the close relationship between both vorticity and divergence and the occurrence of precipitation, few have focused on the deformation of the precipitating atmosphere. In fact, deformation is closely related to the occurrence and distribution of strong precipitation - a relationship explored in a recent study published in Advances in Atmospheric Sciences, the aim being to involve deformation in the diagnosis of precipitation.

In the study, a new parameter, called potential deformation (PD), is derived by scientists from the Institute of Atmospheric Physics, Chinese Academy of Sciences. PD is composed of potential stretching deformation and potential shearing deformation, which are constructed based on the concept of potential vorticity, and it can be verified that PD does not change with coordinate rotation. PD is then used in a simulated mesoscale convective system (MCS) to examine its performance in precipitation diagnosis.

"We find that PD performs well in indicating the heavy precipitation area within the MCS," says LI Na, the first author of the study. During the two band-shaped and cluster-shaped stages of the MCS, large-value areas of PD also present corresponding bands and clusters.

"An analysis of the physical basis for the close correlation between the PD and precipitation shows that PD can reflect the precipitation area because it contains the typical processes for the production of MCS precipitation: warm and moist inflow, a rear inflow jet, cold and dry downward flow, and a surface cold pool," LI goes on to explain. "And all these processes are contained in PD by the three-dimensional gradient of the generalized potential temperature (or moisture), the vertical wind shear and deformation, and thus PD correlates closely with precipitation." According to the study, the correlation coefficient can reach up to 0.7. This implies great potential for using PD in precipitation detection and forecasting.

At present, numerical models represent one of the main ways for predicting precipitation. However, precipitation in numerical models is mainly obtained by parameterization schemes (microphysical parameterization and cumulus parameterization), which contain strong uncertainties. To improve the prediction skill of precipitation by numerical modeling, a number of extended methods have been developed, based on the numerical results, as a complement to the numerical predictions.

"The usefulness of PD lies in that it can also be calculated from numerical prediction results and used as an interpretation technique to indicate precipitation," says Dr. RAN Lingkun, the corresponding author of the study. "The application of the parameter in forecasting precipitation and its comparison to numerical precipitation is a possible avenue of research for our group in the future."
-end-


Institute of Atmospheric Physics, Chinese Academy of Sciences

Related Precipitation Articles:

Rainy season tends to begin earlier in Northern Central Asia
The researchers found robust increase of annual mean precipitation at the end of the 21st century under all modelling scenarios over northern central Asia.
Using cloud-precipitation relationship to estimate cloud water path of mature tropical cyclones
Scientists find the cloud water path of mature tropical cyclones can be estimated by a notable sigmoid function of near-surface rain rate.
Precipitation will be essential for plants to counteract global warming
A new Columbia Engineering study shows that increased water stress--higher frequency of drought due to higher temperatures, is going to constrain the phenological cycle: in effect, by shutting down photosynthesis, it will generate a lower carbon uptake at the end of the season, thus contributing to increased global warming.
Fall precipitation predicts abundance of curly top disease and guides weed management
Transmitted by an insect known as the beet leafhopper, curly top disease is a viral disease affecting many crops, including melons, peppers, sugar beets, and tomatoes.
Study confirms climate change impacted Hurricane Florence's precipitation and size
A new modeling framework showed that Hurricane Florence produced more extreme rainfall and was spatially larger due to human-induced climate change.
Study shows link between precipitation, climate zone and invasive cancer rates in the US
In a new study, researchers provide conclusive evidence of a statistical relationship between the incidence rates of invasive cancer in a given area in the US and the amount of precipitation and climate type (which combines the temperature and moisture level in an area).
Steep momentum gradients play a major role in coastal precipitation
Steep gradients of wind stress and potential temperature enable sustainable nearshore precipitation systems along the western coastal region of Korea.
Increasing precipitation extremes driving tree growth reductions across southwest
As the Earth's temperature warms, its hydrological cycle kicks into overdrive - wet years get wetter, and dry years get drier.
Extreme flooding from storm surge and heavy precipitation projected to increase higher probability of compound flooding from precipitation and storm surge in Europe under anthropogenic climate change
Risk of compound flooding, which can result when rapid sea level rises associated with storms occur along with heavy rains, is currently concentrated along Mediterranean countries but will greatly increase for Northern European in the future as the climate warms, according to a new modeling study.
NASA reveals heavy rainfall in Tropical Cyclone Fani
Satellite data revealed heavy rainfall in powerful Tropical Cyclone Fani before it made landfall in northeastern India.
More Precipitation News and Precipitation Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Making Amends
What makes a true apology? What does it mean to make amends for past mistakes? This hour, TED speakers explore how repairing the wrongs of the past is the first step toward healing for the future. Guests include historian and preservationist Brent Leggs, law professor Martha Minow, librarian Dawn Wacek, and playwright V (formerly Eve Ensler).
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.