Time filter

Source Type

Seattle, WA, United States

The National Oceanic and Atmospheric Administration is a scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere. NOAA warns of dangerous weather, charts seas and skies, guides the use and protection of ocean and coastal resources, and conducts research to improve understanding and stewardship of the environment. In addition to its civilian employees, 12,000 as of 2012, NOAA research and operations are supported by 300 uniformed service members who make up the NOAA Commissioned Officer Corps. The current Under Secretary of Commerce for Oceans and Atmosphere at the Department of Commerce and the agency's administrator is Kathryn D. Sullivan, who was nominated February 28, 2013, and confirmed March 6, 2014. Wikipedia.

Akmaev R.A.,National Oceanic and Atmospheric Administration
Reviews of Geophysics

At the turn of the century R. G. Roble advanced an ambitious program of developing an atmospheric general circulation model (GCM) extending from the surface to the exosphere. He outlined several areas of research and application to potentially benefit from what is now commonly called whole atmosphere modeling. The purpose of this article is to introduce this new field to a broader geophysical community and document its progress over the last decade. Vertically extended models are commonly built from existing weather and climate GCM codes incorporating a number of approximations, which may no longer be valid. Promising directions of further model development, potential applications, and challenges are outlined. One application is space weather or day-to-day and seasonal variability in the ionosphere and thermosphere driven by meteorological processes from below. Various modes of connection between the lower and upper atmosphere had been known before, but new and sometimes unexpected observational evidence has emerged over the last decade. Persistent "nonmigrating" wavy structures in plasma and neutral densities and a dramatic response of the equatorial ionosphere to sudden warmings in the polar winter stratosphere are just two examples. Because large-scale meteorological processes are predictable several days in advance, whole atmosphere weather prediction models open an opportunity for developing a real forecast capability for space weather. © 2011 by the American Geophysical Union. Source

Winton M.,National Oceanic and Atmospheric Administration
Journal of Climate

The sensitivity of Northern Hemisphere sea ice cover to global temperature change is examined in a group of climate models and in the satellite-era observations. The models are found to have well-defined, distinguishable sensitivities in climate change experiments. The satellite-era observations show a larger sensitivity-a larger decline per degree of warming-than any of the models. To evaluate the role of natural variability in this discrepancy, the sensitivity probability density function is constructed based upon the observed trends and natural variability of multidecadal ice cover and global temperature trends in a long control run of the GFDL Climate Model, version 2.1 (CM2.1). This comparison shows that the model sensitivities range from about 1 to more than 2 pseudostandard deviations of the variability smaller than observations indicate. The impact of natural Atlantic multidecadal temperature trends (as simulated by the GFDL model) on the sensitivity distribution is examined and found to be minimal. © 2011 American Meteorological Society. Source

Dunion J.P.,National Oceanic and Atmospheric Administration
Journal of Climate

The Jordan mean tropical sounding has provided a benchmark reference for representing the climatology of the tropical North Atlantic and Caribbean Sea atmosphere for over 50 years. However, recent observations and studies have suggested that during the months of the North Atlantic hurricane season, this region of the world is affected by multiple air masses with very distinct thermodynamic and kinematic characteristics. This study examined;6000 rawinsonde observations from the Caribbean Sea region taken during the core months (July-October) of the 1995-2002 hurricane seasons. It was found that single mean soundings created from this new dataset were very similar to C. L. Jordan's 1958 sounding work. However, recently developed multispectral satellite imagery that can track low- to midlevel dry air masses indicated that the 1995-2002 hurricane season dataset (and likely Jordan's dataset as well) was dominated by three distinct air masses: moist tropical (MT), Saharan air layer (SAL), and midlatitude dry air intrusions (MLDAIs). Findings suggest that each sounding is associated with unique thermodynamic, kinematic, stability, and mean sea level pressure characteristics and that none of these soundings is particularly well represented by a single mean sounding such as Jordan's. This work presents three new mean tropical soundings (MT, SAL, and MLDAI) for the tropical North Atlantic Ocean and Caribbean Sea region and includes information on their temporal variability, thermodynamics, winds, wind shear, stability, total precipitable water, and mean sea level pressure attributes. It is concluded that the new MT, SAL, andMLDAIsoundings presented here provide a more robust depiction of the tropical North Atlantic and Caribbean Sea atmosphere during the Atlantic hurricane season and should replace the Jordan mean tropical sounding as the new benchmark soundings for this part of the world. © 2011 American Meteorological Society. Source

Waples R.S.,National Oceanic and Atmospheric Administration
Proceedings. Biological sciences / The Royal Society

Effective population size (Ne) controls both the rate of random genetic drift and the effectiveness of selection and migration, but it is difficult to estimate in nature. In particular, for species with overlapping generations, it is easier to estimate the effective number of breeders in one reproductive cycle (Nb) than Ne per generation. We empirically evaluated the relationship between life history and ratios of Ne, Nb and adult census size (N) using a recently developed model (agene) and published vital rates for 63 iteroparous animals and plants. Nb/Ne varied a surprising sixfold across species and, contrary to expectations, Nb was larger than Ne in over half the species. Up to two-thirds of the variance in Nb/Ne and up to half the variance in Ne/N was explained by just two life-history traits (age at maturity and adult lifespan) that have long interested both ecologists and evolutionary biologists. These results provide novel insights into, and demonstrate a close general linkage between, demographic and evolutionary processes across diverse taxa. For the first time, our results also make it possible to interpret rapidly accumulating estimates of Nb in the context of the rich body of evolutionary theory based on Ne per generation. Source

Murphy D.M.,National Oceanic and Atmospheric Administration
Nature Geoscience

Aerosols both scatter and absorb incoming solar radiation, with consequences for the energy balance of the atmosphere. Unlike greenhouse gases, atmospheric aerosols are distributed non-uniformly around the Earth. Therefore, regional shifts in aerosol abundance could alter radiative forcing of the climate. Here, I use multi-angle imaging spectroradiometer (MISR) satellite data and the Atmospheric and Environmental Research radiative transfer model to assess the radiative effect of the spatial redistribution of aerosols over the past decade. Unexpectedly, the radiative transfer model shows that the movement of aerosols from high latitudes towards the Equator, as might happen if pollution shifts from Europe to southeast Asia, has little effect on clear-sky radiative forcing. Shorter slant paths and smaller upscatter fractions near the Equator compensate for more total sunlight there. Overall, there has been an almost exact cancellation in the clear-sky radiative forcing from aerosol increases and decreases in different parts of the world, whereas MISR should have been able to easily detect a change of 0.1 W m-2 per decade due to changing patterns. Long-term changes in global mean aerosol optical depth or indirect aerosol forcing of clouds are difficult to measure from satellites. However, the satellite data show that the regional redistribution of aerosols had little direct net effect on global average clear-sky radiative forcing from 2000 to 2012. © 2013 Macmillan Publishers Limited. All rights reserved. Source

Discover hidden collaborations