Nav: Home

A new parameterization of canopy radiative transfer for land surface radiation models

April 07, 2017

Among the physical processes of land surfaces, canopy radiative transfer is especially important. It plays a key role in controlling land-atmosphere flux exchanges by determining surface albedo and transpiration. However, the canopy varies geographically from that of dense tropical forests to the shrublands of arid desert lands, and temporally from the vibrancy of spring to the gloominess of winter. Uncertainties are abound in the processes of radiative transfer parameterization.

Dr Feng Zhang and his collaborators propose a new parameterization for the canopy phase function, which is based on the leaf normal distribution and leaf reflection/transmission, and examine the accuracy in reflection and transmission of the canopy through comparison with the benchmark result of SOSA. The findings are published in Advances in Atmospheric Sciences (Zhang et al., 2017).

"The new method," says Dr. Zhang, "when based on Eddington approximation, can substantially improve the accuracy compared to the previously preferred hemispheric constant method, under both isotropic and anisotropic conditions. Therefore, the canopy albedo can be evaluated more accurately by the analytical solution of non-zero soil background reflection."

Moreover, their investigation also reveals that there is a relationship between the direct radiation and the diffuse radiation of the canopy, which have been treated separately in previous studies. It is concluded that the new parameterization is well suited for applications of land surface radiation modeling.
-end-


Institute of Atmospheric Physics, Chinese Academy of Sciences

Related Transmission Articles:

A molecular rivet for long-range force transmission
Researchers from the Mechanobiology Institute, Singapore at the National University of Singapore have described, for the first time, how plastin, an actin-bundling protein, acts as a molecular rivet, providing global connectivity to the cortex underlying the plasma membrane of embryonic cells to facilitate polarization and cell division.
How Thailand eliminated mother-to-child HIV transmission
Thailand has become the first Asian country to eliminate mother-to-child transmission of HIV, thanks to a pragmatic multi-sector response backed by strong political commitment and heavy government investment, a study published in Paediatrics and International Child Health reports.
Cholesterol important for signal transmission in cells
Cholesterol can bind important molecules into pairs, enabling human cells to react to external signals.
New insight into course and transmission of Zika infection
In one of the first and largest studies of its kind, a research team lead by virologists at Beth Israel Deaconess Medical Center has characterized the progression of two strains of the viral infection.
Over 20 countries environmentally suitable for Ebola transmission by bats
Though the West African Ebola outbreak that began in 2013 is now under control, 23 countries remain environmentally suitable for animal-to-human transmission of the Ebola virus.
Largest HIV transmission study conducted
A new study has found that neither gay men nor heterosexual people with HIV transmit the virus to their partner, provided they are on suppressive antiretroviral treatment.
Decreases in malaria transmission may be followed by increased susceptibility in children
Progress in reducing malaria burden in Africa may have had the paradoxical effect of increasing transmission among older children in recent years, according to research published this week in PLOS Medicine.
Sexual transmission of Ebola likely to impact course of outbreaks
Sexual transmission of the Ebola virus could have a major impact on the dynamics of the disease, potentially reigniting an outbreak that has been contained by public health interventions, according to research by University of Georgia ecologists just published in the Royal Society journal Biology Letters.
Could hepatitis C treatments help prevent virus transmission?
An international team of researchers has shed light on the potential impact of new drugs for hepatitis C virus (HCV).
Scientists identify new route of TB transmission
Scientists have discovered a new species of bacteria, Mycobacterium mungi, that causes tuberculosis (TB) and is transmitted through the skin and nose of banded mongoose in Northern Botswana.

Related Transmission Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...