103 research outputs found
Seasonal heavy precipitation sensitivity to moisture corrections in the western Mediterranean across resolutions
The controlling role of atmospheric water vapour for heavy precipitation leading to extreme events has been widely demonstrated, along with the existing gap of adequate moisture observations and the frequent biases present in model simulations concerning this fundamental variable. In this study, we profit from a state-of-the-art dense network of GPS measurements over Europe retrieving a homogenized GPS-derived Zenith Total Delay (GPS-ZTD) data set up to 10 min of temporal resolution, to assess the seasonal sensitivity of convection-related processes and heavy precipitation modelling to atmospheric humidity corrections. For this purpose, we perform nudging experiments with the COSMO-CLM model at two spatial resolutions, 7 km (parameterized convection) and 2.8 km (explicitly resolved convection) covering the autumn period of 2012, when the Special Observation Period (SOP) 1 of the Hydrological Cycle in the Mediterranean Experiment (HyMeX) program took place in the Western Mediterranean, which is our area of interest.
The benefits and disadvantages of GPS-ZTD nudging and resulting moisture corrections are disentangled. The impact on high-resolution parameterized versus convection-permitting simulations is compared. A process-understanding methodology and a local-to-regional approach are used. Our results show a beneficial impact on the seasonal scale at both model grid spacings improving the representation of the chain of processes leading to heavy precipitation, contrary to the non-systematic improvement at the event and sub-event scales. The correction of atmospheric moisture entails a reduction of about 10% in the total column water vapour and corrections on single locations up to 10 mm counteracting the model wet bias across scales. The location, structure, and amount of total precipitation are positively affected. Particularly, the combination of high-resolution atmospheric humidity observations and fine convection-permitting simulations shows great potential for correction of the precipitation daily cycle, key for accurate precipitation modelling. The difference in the density of local and upstream observational networks and the lack of information on the vertical stratification of moisture are identified weaknesses, which could be determinants in obtaining more accurate corrections on seasonal to sub-seasonal scales after assimilation strategies
An improved perspective in the spatial representation of soil moisture: potential added value of SMOS disaggregated 1 km resolution “all weather” product
This study uses the synergy of multi-resolution soil moisture (SM) satellite
estimates from the Soil Moisture Ocean Salinity (SMOS) mission, a dense
network of ground-based SM measurements, and a soil–vegetation–atmosphere
transfer (SVAT) model, SURFEX (externalized surface), module ISBA
(interactions between soil, biosphere and atmosphere), to examine the benefits of
the SMOS level 4 (SMOS-L4) version 3.0, or “all weather” high-resolution soil moisture
disaggregated product (SMOS-L43.0; ∼1 km).
The added value compared to SMOS level 3 (SMOS-L3; ∼25 km) and SMOS level 2 (SMOS-L2; ∼15 km) is investigated. In situ SM observations over the
Valencia anchor station (VAS; SMOS calibration and validation – Cal/Val – site in
Europe) are used for comparison. The SURFEX (ISBA) model is used to simulate
point-scale surface SM (SSM) and, in combination with high-quality
atmospheric information data, namely from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Système d'analyse
fournissant des renseignements atmosphériques à la neige (SAFRAN) meteorological
analysis system, to obtain a representative SSM mapping over the VAS. The
sensitivity to realistic initialization with SMOS-L43.0 is assessed to simulate the spatial and temporal distribution of SSM.
Results demonstrate the following: (a) All SMOS products correctly capture the temporal
patterns, but the spatial patterns are not accurately reproduced by the
coarser resolutions, probably in relation to the contrast with point-scale in
situ measurements. (b) The potential of the SMOS-L43.0 product is pointed
out to adequately characterize SM spatio-temporal variability, reflecting
patterns consistent with intensive point-scale SSM samples on a daily timescale. The restricted temporal availability of this product dictated by the
revisit period of the SMOS satellite compromises the averaged SSM
representation for longer periods than a day. (c) A seasonal analysis points
out improved consistency during December–January–February and
September–October–November, in contrast to significantly worse correlations in
March–April–May (in relation to the growing vegetation) and June–July–August
(in relation to low SSM values < 0.1 m3 m−3
and low spatial
variability). (d) The combined use of the SURFEX (ISBA) SVAT model with the
SAFRAN system, initialized with SMOS-L43.0 1 km disaggregated data, is
proven to be a suitable tool for producing regional SM maps with high
accuracy, which could be used as initial conditions for model simulations, flood
forecasting, crop monitoring and crop development strategies, among others.</p
Climate change in the next 30 years : What can a convection-permitting model tell us that we did not already know?
To investigate the climate change in the next 30 years over a complex terrain in southwestern Germany, simulations performed with the regional climate model COSMO-CLM at convection-permitting resolution are compared to simulations at 7 km resolution with parameterised convection. An earlier study has shown the main benefits of convection-permitting resolution in the hourly statistics and the diurnal cycle of precipitation intensities. Here, we investigate whether the improved simulation of precipitation in the convection-permitting model is affecting future climate projections in summer. Overall, the future scenario (ECHAM5 with A1B forcing) brings weak changes in mean precipitation, but stronger hourly intensities in the morning and less frequent but more intense daily precipitation. The two model simulations produce similar changes in climate, despite differences in their physical characteristics linked to the formation of convective precipitation. A significant increase in the morning precipitation probably due to large-scale forced convection is found when considering only the most extreme events (above 50 mm/day). In this case, even the diurnal cycles of precipitation and convection-related indices are similar between resolutions, leading to the conclusion that the 7 km model sufficiently resolves the most extreme convective events. In this region and time periods, the 7 km resolution is deemed sufficient for most assessments of near future precipitation change. However, conclusions could be dependent on the characteristics of the region of investigation
GPS – Zenith Total Delay assimilation in different resolution simulations of a heavy precipitation event over southern France
The aim of this study is to investigate the different
pathways of the interaction between an improved atmospheric moisture
distribution by Data Assimilation (DA) of Global Positioning System Zenith Total Delays (GPS-ZTD)
on the simulation of a selected Heavy Precipitation Event (HPE) across different
model horizontal resolutions (7 km, 2.8 km and 500 m). The initiation and
evolution of deep moist convection and heavy precipitation taking place on
the 24 September 2012, which had a dedicated Intensive Observation Period
(IOP6) during the Hydrological cycle in the Mediterranean eXperiment (HyMeX)
Special Observation period 1, are analysed. The results show an improvement
in the representation of the Integrated Water Vapour (IWV) spatial
distribution and temporal evolution when the data assimilation is applied as
well as through the refinement of the model grids. However, important
discrepancies between the simulated and the observed vertical profiles of
humidity still remain after the DA, thus affecting the representation of
convection and heavy precipitation. For the presented case study, the model
simulations exhibited a wet bias. The assimilation entailed a drying of the
low to middle troposphere over the study region during the 6 h prior
to the storm initiation for every horizontal resolution. This reduced the
instability present at the moment of storm initiation, weakening in return
the intensity of convection and the number of cells triggered. The
improvement observed in the atmospheric moisture content and distribution
was not followed by an improved precipitation representation closer to
observations. This highlights the relevance of correctly distributing the
assimilated IWV in the vertical direction in the models
Genomics in premature infants: A non-invasive strategy to obtain high-quality DNA
We used a cost-effective, non-invasive method to obtain high-quality DNA from buccal epithelial-cells (BEC) of premature infants for genomic analysis. DNAs from BEC were obtained from premature infants with gestational age ≤ 36 weeks. Short terminal repeats (STRs) were performed simultaneously on DNA obtained from the buccal swabs and blood from the same patient. The STR profiles demonstrated that the samples originated from the same individual and exclude any contamination by external DNAs. Whole exome sequencing was performed on DNAs obtained from BEC on premature infants with and without necrotizing enterocolitis, and successfully provided a total number of reads and variants corroborating with those obtained from healthy blood donors. We provide a proof of concept that BEC is a reliable and preferable source of DNA for high-throughput sequencing in premature infants
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The convective storm initiation project
Copyright @ 2007 AMSThe Convective Storm Initiation Project (CSIP) is an international project to understand precisely where, when, and how convective clouds form and develop into showers in the mainly maritime environment of southern England. A major aim of CSIP is to compare the results of the very high resolution Met Office weather forecasting model with detailed observations of the early stages of convective clouds and to use the newly gained understanding to improve the predictions of the model. A large array of ground-based instruments plus two instrumented aircraft, from the U.K. National Centre for Atmospheric Science (NCAS) and the German Institute for Meteorology and Climate Research (IMK), Karlsruhe, were deployed in southern England, over an area centered on the meteorological radars at Chilbolton, during the summers of 2004 and 2005. In addition to a variety of ground-based remote-sensing instruments, numerous rawin-sondes were released at one- to two-hourly intervals from six closely spaced sites. The Met Office weather radar network and Meteosat satellite imagery were used to provide context for the observations made by the instruments deployed during CSIP. This article presents an overview of the CSIP field campaign and examples from CSIP of the types of convective initiation phenomena that are typical in the United Kingdom. It shows the way in which certain kinds of observational data are able to reveal these phenomena and gives an explanation of how the analyses of data from the field campaign will be used in the development of an improved very high resolution NWP model for operational use.This work is funded by the National Environment Research Council following an initial award from the HEFCE Joint Infrastructure Fund
Hygienic monitoring of freshwater crayfish (Astacus leptodactylus) on Aras Lake reservoir
Aras dam reservoir situated in the northwest of Iran, west Azarbaijan province, is the only water resource of Astacus leptodactylus harvest in the country that more than 250tons of this species were exported to different countries all over the world, annually. On the other hand, one of the polices of Iranian Science Fisheries Institute is the release of this species into other water resources in the country and for this purpose, the study of risky diseases such as Crayfish pest (Aphanomysis astasi) and other zoonotic diseases are considered as the research priorities of aquaculture development of the country. This study was carried out to health screening of Astacus leptodactylus at Aras dam reservoir from winter 2013 to fall 2014. In this regard, A total of 394 harvested livefreshwater crayfish Astacus leptodactylus (255males, 139females) weretested. 9 epibionts and parasites peritrich protozoans were identified. From Metazoan parasites group, Branchiobdella kozarovi with incidence rate of (100%) in obtained samples was the only isolated organism from this group that identified up to species level. There was a heavy damage in gills of samples with Aeolosoma hemprichi (Annelid) in winter with90% prevalence. Furthermore, Other Epibiont fouling organisms such as Rotatoria; free living nematods and suctoria were observed in this survey. The fungi study of the lesions and melanized spots of mentioned samples revealed their infection to Penicillium expansum; Aspergillus flavus; Alternaria sp. ; Fusarium sp. and Saprolegnia sp. The results of bacterial study confirmed the presence of pathogen bacteria in Astacus leptodactylus. The most frequency percentage (15.16%) in hepatopancrease were related to Aeromonas hydrophila and the least one (1.37%) were due to Yersinia bacteria. Also, only Aeromonas hydrophila and Staphylococcus aureus were isolated and identified from heamolymph, respectively. The results revealed that the combination of Salmonella typhi, Escherichia coli and Staphylococcus sp. has caused the most infection rate while. Yersinia ruckeri and Salmonella typhi has caused the least infections in Astacus leptodactylus. According to the isolation of 6 bacteria species from hepatopancreas and 2 species from heamplymph , it can be concluded that hepatopancreas enjoyed the higher infection rate compared to haemolymph in the obtained samples
Investigation of structure-directing interactions within copper(i)thiocyanate complexes through X-ray analyses and non-covalent interaction (NCI) theoretical approach
Herein, we reported the synthesis of copperIJI) thiocyanate complexes with ortho-pyridinyl carbohydrazones containing a thiophene (L1) or a furyl ring (L2) as a mixture of two different crystals for each compound, linkage isomers of C1N, [CuIJNCS)IJL1)PPh3] and C1S, [Cu(SCN)(L1)PPh3], for L1, whereas monomeric and polymeric structures C2N, [Cu(NCS)(L2)PPh3], and C2P, [–(NCS)Cu(L2)–]n, for L2. Crystallographic information and theoretical calculations, mainly noncovalent interaction reduced density gradient (NCI-RDG) analyses, were pursued to generate a profound understanding of the structure-directing interactions in these complexes. The supramolecular assemblies are first driven by cooperative π⋯π interactions and hydrogen bonds followed by CH⋯π, S⋯S and S⋯π linkages. In the case of the linkage isomers, intermolecular interactions may have a significant role in the formation of the less stable S-bound isomer C1S
Antibody responses to α-Gal in African children vary with age and site and are associated with malaria protection.
Naturally-acquired antibody responses to malaria parasites are not only directed to protein antigens but also to carbohydrates on the surface of Plasmodium protozoa. Immunoglobulin M responses to α-galactose (α-Gal) (Galα1-3Galβ1-4GlcNAc-R)-containing glycoconjugates have been associated with protection from P. falciparum infection and, as a result, these molecules are under consideration as vaccine targets; however there are limited field studies in endemic populations. We assessed a wide breadth of isotype and subclass antibody response to α-Gal in children from Mozambique (South East Africa) and Ghana (West Africa) by quantitative suspension array technology. We showed that anti-α-Gal IgM, IgG and IgG1-4 levels vary mainly depending on the age of the child, and also differ in magnitude in the two sites. At an individual level, the intensity of malaria exposure to P. falciparum and maternally-transferred antibodies affected the magnitude of α-Gal responses. There was evidence for a possible protective role of anti-α-Gal IgG3 and IgG4 antibodies. However, the most consistent findings were that the magnitude of IgM responses to α-Gal was associated with protection against clinical malaria over a one-year follow up period, especially in the first months of life, while IgG levels correlated with malaria risk
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