51 research outputs found
Contrasting Observed Atmospheric Responses to Tropical Sea Surface Temperature Warming Patterns
AM was funded by a NERC doctoral training partnership grant (NE/L002558/1). This study was funded as part of NERC's support of the National Center for Earth Observation: HB and PIP were supported by grant number NE/R016518/1.Equilibrium climate sensitivity (ECS) is a theoretical concept which describes the change in global mean surface temperature that results from a sustained doubling of atmospheric CO2. Current ECS estimates range from âź1.8 to 5.6 K, reflecting uncertainties in climate feedbacks. The sensitivity of the lower (1,000â700 hPa) and upper (500â200 hPa) troposphere to changes in spatial patterns of tropical sea surface temperature (SST) have been proposed by recent model studies as key feedbacks controlling climate sensitivity. We examine empirical evidence for these proposed mechanisms using 14 years of satellite data. We examine the response of temperature and humidity profiles, clouds, and topâofâtheâatmosphere radiation to relative warming in tropical ocean regions when there is either strong convection or subsidence. We find warmer SSTs in regions of strong subsidence are coincident with a decrease in lower tropospheric stability (â0.9 Âą 0.4 KKâ1) and low cloud cover (âźâ6% Kâ1). This leads to a warming associated with the weakening in the shortwave cooling effect of clouds (4.2 Âą 1.9 Wmâ2Kâ1), broadly consistent with model calculations. In contrast, warmer SSTs in regions of strong convection are coincident with an increase in upper tropospheric humidity (3.2 Âą 1.5% Kâ1). In this scenario, the dominant effect is the enhancement of the warming longwave cloud radiative effect (3.8 Âą 3.0 Wmâ2Kâ1) from an increase in high cloud cover (âź7% Kâ1), though changes in the net (longwave and shortwave) effect are not statistically significant (p < 0.003). Our observational evidence supports the existence of mechanisms linking contrasting atmospheric responses to patterns in SST, mechanisms which have been linked to climate sensitivity.Publisher PDFPeer reviewe
Observed and CMIP5âSimulated Radiative Flux Variability Over West Africa
We explore the ability of general circulation models in the Coupled Model Intercomparison Project (CMIP5) to recreate observed seasonal variability in topâofâtheâatmosphere and surface radiation fluxes over West Africa. This tests CMIP5 models' ability to describe the radiative energy partitioning, which is fundamental to our understanding of the current climate and its future changes. We use 15 years of the monthly Clouds and the Earth's Radiant Energy System Energy Balanced and Filled (EBAF) product, alongside other satellite, reanalysis, and surface station products. We find that the CMIP5 multimodel mean is generally within the reference product range, with annual mean CMIP5 multimodel meanâEBAF of â0.5 W mâ2 for topâofâtheâatmosphere reflected shortwave radiation, and 4.6 W mâ2 in outgoing longwave radiation over West Africa. However, the range in annual mean of the model seasonal cycles is large (37.2 and 34.0 W mâ2 for reflected shortwave radiation and outgoing longwave radiation, respectively). We use seasonal and regional contrasts in allâsky fluxes to infer that the representation of the West African monsoon in numerical models affects radiative energy partitioning. Using clearâsky surface fluxes, we find that the models tend to have more downwelling shortwave and less downwelling longwave radiation than EBAF, consistent with past research. We find models that are drier and have lower aerosol loading tend to show the largest differences. We find evidence that aerosol variability has a larger effect in modulating downwelling shortwave radiation than water vapor in EBAF, while the opposite effect is seen in the majority of CMIP5 models.ISSN:2333-508
Solar cooking in the sahel
Solar cookers are a cheap, practical tool for sustainable development, which can be built and maintained without access to expensive tools or machinery. Solar cookers require direct sunshine for effective cooking, so clouds or heavy atmospheric dust loads can slow down or prevent their use. Surface meteorological (SYNOP) stations record the daily hours of direct sunshine and were used to generate climatology of days with greater than 6 h available for cooking. The SYNOP dataset is very sparse in many parts of Africa and therefore is complemented by the use of geostationary satellite data. Higher temporal resolution surface insolation records are derived from SEVIRI (Spinning Enhanced Visible and Infrared Imager) on board the Meteosat Second Generation satellite series by EUMETSAT's Land Satellite Application Facility, but the approach uses fixed aerosol climatology. Direct surface solar irradiance was derived using the Beer-Lambert law using AODs retrieved from SEVIRI. Validation indicates that its capabilities are strongest over drier and less vegetated surfaces such as those found in the Sahara and Sahel. Biomass-burning aerosol may be significant over the Sahel in winter, and SEVIRI AODs may miss this unless it is masked as cloud, although here SYNOP values are still greater than those from SEVIRI
The Iowa Homemaker vol.3, no.3-4
Table of Contents
The Architectural Design of a Home by Allen Holmes Kimball, page 1
âFor a Manâs House Is His Castleâ by Alda Wilson, page 2
The Economics of Consumption compiled by John E. Brindley, page 3
Sunfast and Tubfast Materials by Pearl Apland, page 5
On Our Street by Juanita J. Beard, page 6
Who Is Responsible for the Child? by Orange H. Cessna, page 7
Summer Suppers by N. Beth Bailey, page 8
Vacation First Aid by Dr. Mary Sheldon, page 9
Episodes Concerning Evolution of Home Economics by Ruth Elaine Wilson, page 10
Extravagant Economics by Blanche Ingersoll, page 11
Breakfast Bridge by Eleanor Murray, page 12
Veishea Celebrates First Birthday by Helen G. Lamb, page 1
Can downwelling far-infrared radiances over Antarctica be estimated from mid-infrared information?
Far-infrared (FIR: 100cmâ1<wavenumber, ν<667âcmâ1) radiation emitted by the Earth and its atmosphere plays a key role in the Earth's energy budget. However, because of a lack of spectrally resolved measurements, radiation schemes in climate models suffer from a lack of constraint across this spectral range. Exploiting a method developed to estimate upwelling far-infrared radiation from mid-infrared (MIR: 667cmâ1<ν<1400âcmâ1) observations, we explore the possibility of inferring zenith FIR downwelling radiances in zenith-looking observation geometry, focusing on clear-sky conditions in Antarctica. The methodology selects a MIR predictor wavenumber for each FIR wavenumber based on the maximum correlation seen between the different spectral ranges. Observations from the REFIR-PAD instrument (Radiation Explorer in the Far Infrared â Prototype for Application and Development) and high-resolution radiance simulations generated from co-located radio soundings are used to develop and assess the method. We highlight the impact of noise on the correlation between MIR and FIR radiances by comparing the observational and theoretical cases. Using the observed values in isolation, between 150 and 360âcmâ1, differences between the âtrueâ and âextendedâ radiances are less than 5â%. However, in spectral bands of low signal, between 360 and 667âcmâ1, the impact of instrument noise is strong and increases the differences seen. When the extension of the observed spectra is performed using regression coefficients based on noise-free radiative transfer simulations the results show strong biases, exceeding 100â% where the signal is low. These biases are reduced to just a few percent if the noise in the observations is accounted for in the simulation procedure. Our results imply that while it is feasible to use this type of approach to extend mid-infrared spectral measurements to the far-infrared, the quality of the extension will be strongly dependent on the noise characteristics of the observations. A good knowledge of the atmospheric state associated with the measurements is also required in order to build a representative regression model
Transcriptomic Coordination in the Human Metabolic Network Reveals Links between n-3 Fat Intake, Adipose Tissue Gene Expression and Metabolic Health
Understanding the molecular link between diet and health is a key goal in nutritional systems biology. As an alternative to pathway analysis, we have developed a joint multivariate and network-based approach to analysis of a dataset of habitual dietary records, adipose tissue transcriptomics and comprehensive plasma marker profiles from human volunteers with the Metabolic Syndrome. With this approach we identified prominent co-expressed sub-networks in the global metabolic network, which showed correlated expression with habitual n-3 PUFA intake and urinary levels of the oxidative stress marker 8-iso-PGF2Îą. These sub-networks illustrated inherent cross-talk between distinct metabolic pathways, such as between triglyceride metabolism and production of lipid signalling molecules. In a parallel promoter analysis, we identified several adipogenic transcription factors as potential transcriptional regulators associated with habitual n-3 PUFA intake. Our results illustrate advantages of network-based analysis, and generate novel hypotheses on the transcriptomic link between habitual n-3 PUFA intake, adipose tissue function and oxidative stress
An investigation into the impact of greenhouse gas forcings on the terrestrial radiation field : sensitivity studies at high spectral resolution.
Imperial Users onl
Exploring task difficulty in ESL listening assessment
This article reports on an exploratory study that investigated the comparability of listening assessment tasks used to assess and report learning outcomes of adult ESL learners in Australia. The study focused on the effects of task characteristics and task conditions on learnersâ performance in competency-based listening assessment tasks that require learners to demonstrate specific listening behaviours. Key variables investigated included the nature of the input and the response mode. Quantitative and qualitative analyses of test scores suggest that speech rate and item format influence task and item difficulty. However, the complexity of the interaction between text, item and response makes it difficult to isolate the effects of specific variables. Implications of these findings for assessment task validity and reliability are considered and practical consequences for assessment task design in outcomes-based systems are discussed.26 page(s
Electronic patient records: The impact on the therapeutic relationship
A look at confidentiality issues arising from the use of electronic records, adding a consideration of the subject from
a psychoanalytic perspectiv
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