125 research outputs found
Data Assimilation of AIRS Water Vapor Profiles: Impact on Precipitation Forecasts for Atmospheric River Cases Affecting the Western of the United States
Atmospheric rivers are transient, narrow regions in the atmosphere responsible for the transport of large amounts of water vapor. These phenomena can have a large impact on precipitation. In particular, they can be responsible for intense rain events on the western coast of North America during the winter season. This paper focuses on attempts to improve forecasts of heavy precipitation events in the Western US due to atmospheric rivers. Profiles of water vapor derived from from Atmospheric Infrared Sounder (AIRS) observations are combined with GFS forecasts by a three-dimensional variational data assimilation in the Gridpoint Statistical Interpolation (GSI). Weather Research and Forecasting (WRF) forecasts initialized from the combined field are compared to forecasts initialized from the GFS forecast only for 3 test cases in the winter of 2011. Results will be presented showing the impact of the AIRS profile data on water vapor and temperature fields, and on the resultant precipitation forecasts
Impact of AIRS Thermodynamic Profiles on Precipitation Forecasts for Atmospheric River Cases Affecting the Western United States
No abstract availabl
An improved near-surface specific humidity and air temperature climatology for the SSM/I satellite period
Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 32 (2015): 412–433, doi:10.1175/JTECH-D-14-00080.1.A near-surface specific humidity (Qa) and air temperature (Ta) climatology on daily and 0.25° grids was constructed by the objectively analyzed air–sea fluxes (OAFlux) project by objectively merging two recent satellite-derived high-resolution analyses, the OAFlux existing 1° analysis, and atmospheric reanalyses. The two satellite products include the multi-instrument microwave regression (MIMR) Qa and Ta analysis and the Goddard Satellite-Based Surface Turbulent Fluxes, version 3 (GSSTF3), Qa analysis. This study assesses the degree of improvement made by OAFlux using buoy time series measurements at 137 locations and a global empirical orthogonal function (EOF) analysis. There are a total of 130 855 collocated daily values for Qa and 283 012 collocated daily values for Ta in the buoy evaluation. It is found that OAFlux Qa has a mean difference close to 0 and a root-mean-square (RMS) difference of 0.73 g kg−1, and Ta has a mean difference of −0.03°C and an RMS difference of 0.45°C. OAFlux shows no major systematic bias with respect to buoy measurements over all buoy locations except for the vicinity of the Gulf Stream boundary current, where the RMS difference exceeds 1.8°C in Ta and 1.2 g kg−1 in Qa. The buoy evaluation indicates that OAFlux represents an improvement over MIMR and GSSTF3. The global EOF-based intercomparison analysis indicates that OAFlux has a similar spatial–temporal variability pattern with that of three atmospheric reanalyses including MERRA, NCEP-1, and ERA-Interim, but that it differs from GSSTF3 and the Climate Forecast System Reanalysis (CFSR).This study was supported by the NOAA Ocean Climate Observation (OCO) program under Grant NA09OAR4320129.2015-09-0
Laboratory Astrophysics and the State of Astronomy and Astrophysics
Laboratory astrophysics and complementary theoretical calculations are the
foundations of astronomy and astrophysics and will remain so into the
foreseeable future. The impact of laboratory astrophysics ranges from the
scientific conception stage for ground-based, airborne, and space-based
observatories, all the way through to the scientific return of these projects
and missions. It is our understanding of the under-lying physical processes and
the measurements of critical physical parameters that allows us to address
fundamental questions in astronomy and astrophysics. In this regard, laboratory
astrophysics is much like detector and instrument development at NASA, NSF, and
DOE. These efforts are necessary for the success of astronomical research being
funded by the agencies. Without concomitant efforts in all three directions
(observational facilities, detector/instrument development, and laboratory
astrophysics) the future progress of astronomy and astrophysics is imperiled.
In addition, new developments in experimental technologies have allowed
laboratory studies to take on a new role as some questions which previously
could only be studied theoretically can now be addressed directly in the lab.
With this in mind we, the members of the AAS Working Group on Laboratory
Astrophysics, have prepared this State of the Profession Position Paper on the
laboratory astrophysics infrastructure needed to ensure the advancement of
astronomy and astrophysics in the next decade.Comment: Position paper submitted by the AAS Working Group on Laboratory
Astrophysics (WGLA) to the State of the Profession (Facilities, Funding and
Programs Study Group) of the Astronomy and Astrophysics Decadal Survey
(Astro2010
Recommended from our members
A new high-resolution sea surface temperature blended analysis
The National Oceanic and Atmospheric Administration’s (NOAA) office of National Environmental Satellite, Data, and Information Service (NESDIS) now generates a daily 0.05° (∼5 km) global high-resolution satellite-based sea surface temperature (SST) analyses on an operational basis. The new analysis combines SST data from U.S., Japanese, and European geostationary infrared imagers, and low-Earth-orbiting infrared (United States and Europe) SST data, into a single high-resolution 5-km product. An earlier version produced a 0.1° (∼11 km) resolution, a resolution chosen to approximate the Nyquist sampling criterion for the midlatitude Rossby radius (∼20 km), in order to preserve mesoscale oceanographic features such as eddies and frontal meanders. Comparison between the two analyses illustrates that the higher-resolution grid spacing has more success in this regard. The analysis employs a rigorous multiscale optimum interpolation (OI) methodology that approximates the Kalman filter, together with a data-adaptive correlation length scale, to ensure a good balance between detail preservation and noise reduction. The product accuracy verified against globally distributed buoys is ∼0.02 K, with a robust standard deviation of ∼0.25 K. The new analysis has proven a significant success even when compared to other products that purport to have a similar resolution. This analysis forms the basis for other operational environmental products such as coral reef bleaching risk and ocean heat content for tropical cyclone prediction. Forthcoming enhancements include the incorporation of microwave SST products from low-Earth-orbiting platforms [e.g., Global Change Observation Mission for Water-1 (GCOM-W1)] in order to improve the resolution of SST features in areas of persistent cloud and correct for diurnal effects via a turbulence model of upper-ocean heating
Ocean Winds and Turbulent Air-Sea Fluxes Inferred From Remote Sensing
Air-sea turbulent fluxes determine the exchange of momentum, heat, freshwater, and gas between the atmosphere and ocean. These exchange processes are critical to a broad range of research questions spanning length scales from meters to thousands of kilometers and time scales from hours to decades. Examples are discussed (section 2). The estimation of surface turbulent fluxes from satellite is challenging and fraught with considerable errors (section 3); however, recent developments in retrievals (section 3) will greatly reduce these errors. Goals for the future observing system are summarized in section 4. Surface fluxes are defined as the rate per unit area at which something (e.g., momentum, energy, moisture, or CO Z ) is transferred across the air/sea interface. Wind- and buoyancy-driven surface fluxes are called surface turbulent fluxes because the mixing and transport are due to turbulence. Examples of nonturbulent processes are radiative fluxes (e.g., solar radiation) and precipitation (Schmitt et al., 2010). Turbulent fluxes are strongly dependent on wind speed; therefore, observations of wind speed are critical for the calculation of all turbulent surface fluxes. Wind stress, the vertical transport of horizontal momentum, also depends on wind direction. Stress is very important for many ocean processes, including upper ocean currents (Dohan and Maximenko, 2010) and deep ocean currents (Lee et al., 2010). On short time scales, this horizontal transport is usually small compared to surface fluxes. For long-term processes, transport can be very important but again is usually small compared to surface fluxes
Interannual Variability of Tropical Ocean Evaporation: A Comparison of Microwave Satellite and Assimilation Results
Remote sensing methodologies for turbulent heat fluxes over oceans depend on driving bulk formulations of fluxes with measured surface winds and estimated near surface thermodynamics from microwave sensors of the Special Sensor Microwave Imager (SSM/I) heritage. We will review recent work with a number of SSM/I-based algorithms and investigate the ability of current data sets to document global, tropical ocean-averaged evaporation changes in association with El Nino and La Nina SST changes. We show that in addition to interannual signals, latent heat flux increases over the period since late 1987 range from approx. .1 to .6 mm/ day are present; these represent trends 2 to 3 times larger than the NCEP Reanalysis. Since atmospheric storage cannot account for the difference, and since compensating evapotranspiration changes over land are highly unlikely to be this large, these evaporation estimates cannot be reconciled with ocean precipitation records such as those produced by the Global Precipitation Climatology Project, GPCP. The reasons for the disagreement include less than adequate intercalibration between SSM/I sensors providing winds and water vapor for driving the algorithms, biases due to the assumption that column integrated water vapor mirrors near surface water vapor variations, and other factors as well. The reanalyses have their own problems with spin-up during assimilation, lack of constraining input data at the ocean surface, and amplitude of synoptic transients
Development and application of a microarray meter tool to optimize microarray experiments
<p>Abstract</p> <p>Background</p> <p>Successful microarray experimentation requires a complex interplay between the slide chemistry, the printing pins, the nucleic acid probes and targets, and the hybridization milieu. Optimization of these parameters and a careful evaluation of emerging slide chemistries are a prerequisite to any large scale array fabrication effort. We have developed a 'microarray meter' tool which assesses the inherent variations associated with microarray measurement prior to embarking on large scale projects.</p> <p>Findings</p> <p>The microarray meter consists of nucleic acid targets (reference and dynamic range control) and probe components. Different plate designs containing identical probe material were formulated to accommodate different robotic and pin designs. We examined the variability in probe quality and quantity (as judged by the amount of DNA printed and remaining post-hybridization) using three robots equipped with capillary printing pins.</p> <p>Discussion</p> <p>The generation of microarray data with minimal variation requires consistent quality control of the (DNA microarray) manufacturing and experimental processes. Spot reproducibility is a measure primarily of the variations associated with printing. The microarray meter assesses array quality by measuring the DNA content for every feature. It provides a post-hybridization analysis of array quality by scoring probe performance using three metrics, a) a measure of variability in the signal intensities, b) a measure of the signal dynamic range and c) a measure of variability of the spot morphologies.</p
Perception of upper lip augmentation utilizing simulated photography
Background No head to head comparison is available between surgical lip lifting and upper lip filler injections to decide which technique yields the best results in patients. Despite the growing popularity of upper lip augmentation, its effect on societal perceptions of attractiveness, successfulness and overall health in woman is unknown. Methods Blinded casual observers viewed three versions of independent images of 15 unique patient lower faces for a total of 45 images. Observers rated the attractiveness, perceived success, and perceived overall health for each patient image. Facial perception questions were answered on a visual analog scale from 0 to 100, where higher scores corresponded to more positive responses. Results Two hundred and seventeen random observers with an average age of 47 years (standard deviation, 15.9) rated the images. The majority of observers were females (n=183, 84%) of white race (n=174, 80%) and had at least some college education (n=202, 93%). The marginal mean score for perceived attractiveness from the natural condition was 1.5 points (95% confidence interval [CI], 0.9–2.18) higher than perceived attractiveness from the simulated upper lip filler injection condition, and 2.6 points higher (95% CI, 1.95–3.24) than the simulated upper lip lift condition. There was a moderate to strong correlation between the scores of the same observer. Conclusions Simulated upper lip augmentation is amenable to social perception analysis. Scores of the same observer for attractiveness, successfulness, and overall health are strongly correlated. Overall, the natural condition had the highest scores in all categories, followed by simulated upper lip filler, and lastly simulated upper lip lift
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