The Climate and Radiation Lab (CRL) has a very active group studying the climate and health impacts of airborne particles ("aerosols"). Aerosol particles reflect sunlight, which tends to cool surfaces locally. Some also absorb sunlight, warming and stabilizing the ambient atmosphere while still cooling the surface below, sometimes suppressing cloud formation, and even affecting large-scale atmospheric circulation...
Clouds play an important role in weather and climate on local to global scales. Clouds reflect sunlight and trap heat, affecting the Earth’s heat budget. The release of latent heat energy through the formation of clouds and precipitation is an important heat source for the atmosphere, affecting the large-scale circulations of the atmosphere.
The circulation of the atmosphere is affected by the horizontal, vertical, and temporal distribution of atmospheric constituents such as water vapor, aerosols, clouds, precipitation, and latent heat released by cloud formation. Improving our ability to predict weather and climate depends upon accurate representation of these constituents in the vertical dimension. However, the depth and turbulence of the atmosphere make observing gases and microscopic particles in the vertical dimension, i.e., profiling, particularly challenging.
Aerosol dynamics are a global phenomena that affect all aspects of remote sensing from the UV through the near infrared spectrum. Thus it is part of the signal for any remote sensing of vegetation, ocean and atmosphere and is critical for quantifying Earth radiative forcing. Due to the high variability of aerosols over space and time, the contribution to the signal can range from insignificant to dominant. The IPCC has reported that aerosols remain the most uncertain component to quantify the anthropogenic forcing of the earth.
Land-atmosphere fluxes of energy, water, and carbon exert a strong control on atmospheric properties, and thus provide a key forcing for global climate. GSFC has a long history of incorporating remotely sensed data on land properties into land-atmosphere models, including the pioneering Simple Biosphere (SiB) model. This work extends to understanding how human land use, including urbanization, affects regional and global climate.
Disturbance processes such as fire, logging, and insect damage are an integral aspect of how ecosystems change through time. In addition, there is evidence for increased disturbance frequency and altered regrowth patterns due to recent climate change. These changes to disturbance regimes have significant implications for land-climate feedbacks and ecosystem services.
Global land carbon flux from CASA-GFED model (courtesy G. James Collatz)
The goal of climate analysis is to better understand the Earth’s past and present climate, and to predict future climate response to changes in natural and human-induced factors, such as the Sun, greenhouse gases (e.g., water vapor, carbon dioxide and methane), and aerosols (e.g., from dust storms, pollution, fires, sea spray or volcanic eruptions). Climate analysis studies are routinely carried out using a mix of data from diverse sources including historical climate data, current and past satellite instruments, field campaigns, and outputs from regional and global numerical models.
Clouds play a critical role in the Earth's hydrologic cycle and in the energy balance of the climate system. They have a strong effect on solar heating by reflecting part of the incident solar radiation back to space...
Climate and weather fluctuations leading to extreme temperatures, storm surges, flooding, and droughts produce conditions that precipitate mosquito-borne disease epidemics directly affecting global public health. Abnormally high temperatures affect populations of mosquito disease vectors by influencing: mosquito survival; susceptibility of mosquitoes to viruses; mosquito population growth rate, distribution, and seasonality; replication and extrinsic incubation period of a virus in the mosquito; and virus transmission patterns and seasonality.
Advances in our understanding of global hydrological processes will require detailed precipitation estimates on a broad range of time and space scales. Satellite observations provide a critical contribution toward mapping global rainfall and its variability. Over long time periods, monthly records of precipitation will prove valuable in determining global and regional precipitation trends and possibly separating anthropogenic changes from the large natural variations in rainfall.
The Sun is a distant source of energy that reaches the Earth as solar radiation. Solar radiation has a rich spectral structure. It consists of ultra-violet radiation largely absorbed by stratospheric ozone, visible radiation to which the atmosphere is mostly transparent, and near-infrared and solar infrared radiation where some absorption by atmospheric water vapor occurs.
The Sun’s illumination is the ultimate energy source for the Earth's biosphere, and the ultimate driving force for atmospheric, and oceanic circulations. The Sun is a variable star as one can see from sunspots recorded back to Galileo’s time in the early 1600s. Satellite observations over the past three decades show that the sunspot activity is associated with changes in solar output energy.
The reflectance of natural surfaces depends on the view geometry, i.e., the position of the observer or measuring instrument relative to the Sun. Land surfaces usually appear darker in the forward scattering direction (i.e, with the Sun in front of the observer) and significantly brighter in the backscattering direction (i.e., with the Sun behind the observer).
Sophisticated display technology is required to analyze and understand the massive quantities of meteorological data being produced by satellite and other data collection systems, and from simulations from 3-dimensional models. As part of NASA's public out reach activities, the availability of such data sets via the Internet and World Wide Web is being expanded. This section describes the role of staff in this regard.
70% of the Earth’s surface is covered by oceans. It is the only inner planet where all three phases of water (liquid, ice, and vapor) coexist. The movement of water in its different forms, and the perpetual water phase changes are essential ingredients of the planetary water cycle (also known as the hydrological cycle). Precipitation is a major component of the water cycle, and is responsible for most of the fresh water on the planet.