Assimilation of LEANDRE II water observations: impact study on the HyMeX SOP1 precipitation forecasts

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Patterns of morphological variation in two sexually dimorphic bird species with different tail shapes.

7 pagesInternational audienceMany studies have focused on tail ornamentation in birds, but not all tail shapes have been studied in depth. Graduated and pin tails have received less attention than forked tails, despite being more likely, in terms of aerodynamic theory, to be honest signals. We report morphological variation in live specimens of two sexually dimorphic passerines from the same site with different tail shapes: graduated (Cape sugarbird Promerops cafer ) and pin (orangebreasted sunbird Antobaphes violacea ). Coefficients of variation (CVs) were calculated for all morphological traits, both non-ornamental (range 1.91–5.72) and ornamental (range 5.83–21.71). Males and females did not differ in CV for any non-ornamental trait. Ornamental traits in males of both species were significantly more variable than all non-ornamental traits. Cape sugarbird ornamental traits were significantly more variable than those of orangebreasted sunbirds. The high levels of variation in graduated tails relative to pintails suggest that these traits have been driven mainly by sexual selection. In contrast, both constraining natural and multiple ornament selection could be responsible for the relatively low levels of variation in pintails

Retrieval of cloud properties using CALIPSO Imaging Infrared Radiometer. Part I: effective emissivity and optical depth

International audienceThe paper describes the operational analysis of the Imaging Infrared Radiometer (IIR) data, which have been collected in the framework of the CALIPSO mission for the purpose of retrieving high altitude (above 7 km) cloud effective emissivity and optical depth that can be used in synergy with the vertically resolved CALIOP lidar co-located observations. After an IIR scene classification is built under the CALIOP track, the analysis is applied to features detected by CALIOP when found alone in the atmospheric column or when CALIOP identifies an opaque layer underneath. The fast-calculation radiative transfer FASRAD model fed by ancillary meteorological and surface data is used to compute the different components involved in the effective emissivity retrievals under the CALIOP track. The track analysis is extended to the IIR swath using homogeneity criteria based on radiative equivalence. The effective optical depth at 12.05 μm is shown to be a good proxy for about half of the cloud optical depth, allowing direct comparisons with other data bases in the visible spectrum. A step-by-step quantitative sensitivity and performance analysis is provided. The method is validated through comparisons of co-located IIR and CALIOP optical depths for elevated single layered semi-transparent cirrus clouds, showing an excellent agreement (within 20%) for values ranging from 1 down to 0.05. Uncertainties have been determined from the identified error sources. The optical depth distribution of semi-transparent clouds is found to have a nearly exponential shape with a mean value of about 0.5 to 0.6

Retrieval of cloud properties using CALIPSO Imaging Infrared Radiometer. Part II: effective diameter and ice water path

International audienceThe paper describes the version 3 Level 2 operational analysis of the Imaging Infrared Radiometer (IIR) data collected in the framework of the CALIPSO mission to retrieve cirrus cloud effective diameter and ice water path in synergy with the CALIOP lidar co-located observations. The analysis uses a multi-sensor split-window technique relying on the concept of microphysical index applied to the two pairs of channels (12.05, 10.6 μm) and (12.05, 8.65 μm) to retrieve cirrus microphysical properties (effective diameter, ice water path) at 1-km pixel resolution. Retrievals are performed for three crystal families selected from pre-computed Look-Up Tables identified as representative of the main relationships between the microphysical indices. The uncertainties in the microphysical indices are detailed and quantified, and the impact on the retrievals is simulated. The possible biases have been assessed through consistency checks based on effective emissivity difference. It has been shown that particle effective diameters of single-layered cirrus clouds can be retrieved, for the first time, down to effective emissivities close to 0.05 when accurate measured background radiances can be used and up to 0.95 over ocean, land, as well as over low opaque clouds. The retrieval of the ice water path from the IIR effective optical depth and the effective diameter is discussed. Taking advantage of the cloud boundaries retrieved by CALIOP, an IIR power law relationship between ice water content and extinction is established for four temperature ranges and shown to be consistent with previous results on average for the chosen data set

Characterization of volcanic material from combined IR-lidar observations in the frame of the CALIPSO mission

International audienceImportant volcanic material injections in the troposphere can induce significant environmental and meteorological perturbations. Several volcanic eruptions have been recently observed before the eruption of Eyjafjallajökull in Iceland, but this one was an important source of problems to European air transport, as this volcano was directly injecting material over northern Europe. It has thus become of major importance to precisely characterize transported material (identify silicate and sulfate aerosol and their properties) from observations and provide such information as inputs and control to transport models. IR observations have long been used to characterize volcanic emitted material. It is one of the advantages of the CALIPSO mission to combine IR and lidar instruments to provide co-located observations directly exploitable to improve the characterization of aerosol and clouds. CALIPSO, as part of the A-Train, further benefits from an unprecedented observational environment, which enables combined analyses with CloudSat and AQUA. Furthermore, the overpasses of the A-Train provide a snapshot into observations from geostationary platforms, such as MSG over Europe and Africa, which can be of valuable interest to follow the dispersion and modifications of plumes on a regular basis. In this presentation, we will focus on observations made after the eruption of the Chaiten volcano in Chile in 2008, and of the Icelandic volcano in 2010. Emitted plumes were transported over areas possibly covered with low clouds, so that potential observations from the surface need to be complemented, and that radiometric observations in the visible are largely perturbed. We show that the complementary observations of A-Train and geostationary sensors allow to better identify and characterize volcanic ash properties, and to follow the evolution of the plumes. More specifically, we focus on IR observations to characterize the size of silicate particles, and on combined CALIPSO IIR and lidar observations, involving newly developed research products, to analyze aerosol optical depths over clouds and ocean

Characterization of volcanic material from combined IR-lidar observations in the frame of the CALIPSO mission

International audienceImportant volcanic material injections in the troposphere can induce significant environmental and meteorological perturbations. Several volcanic eruptions have been recently observed before the eruption of Eyjafjallajökull in Iceland, but this one was an important source of problems to European air transport, as this volcano was directly injecting material over northern Europe. It has thus become of major importance to precisely characterize transported material (identify silicate and sulfate aerosol and their properties) from observations and provide such information as inputs and control to transport models. IR observations have long been used to characterize volcanic emitted material. It is one of the advantages of the CALIPSO mission to combine IR and lidar instruments to provide co-located observations directly exploitable to improve the characterization of aerosol and clouds. CALIPSO, as part of the A-Train, further benefits from an unprecedented observational environment, which enables combined analyses with CloudSat and AQUA. Furthermore, the overpasses of the A-Train provide a snapshot into observations from geostationary platforms, such as MSG over Europe and Africa, which can be of valuable interest to follow the dispersion and modifications of plumes on a regular basis. In this presentation, we will focus on observations made after the eruption of the Chaiten volcano in Chile in 2008, and of the Icelandic volcano in 2010. Emitted plumes were transported over areas possibly covered with low clouds, so that potential observations from the surface need to be complemented, and that radiometric observations in the visible are largely perturbed. We show that the complementary observations of A-Train and geostationary sensors allow to better identify and characterize volcanic ash properties, and to follow the evolution of the plumes. More specifically, we focus on IR observations to characterize the size of silicate particles, and on combined CALIPSO IIR and lidar observations, involving newly developed research products, to analyze aerosol optical depths over clouds and ocean

Validation of IIR/CALIPSO Level 1 Measurements by Comparison with Collocated Airborne Observations during CIRCLE-2 and Biscay '08 Campaigns

International audienceIn the frame of validation of the spatial observations from the radiometer IIR onboard CALIPSO, the two airborne campaigns 'CIRCLE-2' and 'Biscay 08' took place in 2007 and 2008 in the western part of France, over the Atlantic Ocean. During these experiments, remote sensing measurements were made over cirrus clouds, right under the track of CALIPSO in space and time collocation. For this purpose, a Falcon-20 aircraft was equipped with the lidar LEANDRE-NG and the thermal infrared radiometer CLIMAT-AV, whose spectral characteristics are strongly similar to those of IIR. In situ measurements were also taken in cirrus clouds during 'CIRCLE-2'. After comparisons, consistent agreements are found between brightness temperatures measured by CLIMAT-AV and IIR. However, deviations in the brightness temperature measurements are still observed, mainly in the 8.6-μm channels. Simulations using a radiative transfer code are performed along a perfectly clear sky area to show that these dissimilarities are inherent in slight differences between the spectral channels of both radiometers, and in differences between their altitudes. Cloudy and imperfectly clear areas are found to be harder to interpret, but the measurements are still coherent by taking into account experimental uncertainties. In the end, IIR measurements can be validated unambiguously

Disentangling the origins of confidence in speeded perceptual judgments through multimodal imaging

The human capacity to compute the likelihood that a decision is correct-known as metacognition-has proven difficult to study in isolation as it usually cooccurs with decision making. Here, we isolated postdecisional from decisional contributions to metacognition by analyzing neural correlates of confidence with multimodal imaging. Healthy volunteers reported their confidence in the accuracy of decisions they made or decisions they observed. We found better metacognitive performance for committed vs. observed decisions, indicating that committing to a decision may improve confidence. Relying on concurrent electroencephalography and hemodynamic recordings, we found a common correlate of confidence following committed and observed decisions in the inferior frontal gyrus and a dissociation in the anterior prefrontal cortex and anterior insula. We discuss these results in light of decisional and postdecisional accounts of confidence and propose a computational model of confidence in which metacognitive performance naturally improves when evidence accumulation is constrained upon committing a decision

Overview of the HAIC “Space-borne Observation and Nowcasting of High Ice Water Content Regions” Sub-Project and Mid-Term Results

International audienceThe High Altitude Ice Crystals (HAIC) Sub-Project 3 (SP3) focuses on the detection of cloud regions with high ice water content (IWC) from current available remote sensing observations of space-based geostationary and low-orbit missions. The SP3 activities are aimed at supporting operationally the two up-coming HAIC flight campaigns (the first one in May 2015 in Cayenne, French Guyana; the second one in January 2016 in Darwin, Australia) and ultimately provide near real-time cloud monitoring to Air Traffic Management. More in detail the SP3 activities focus on the detection of high IWC from space-borne geostationary Meteosat daytime imagery, explore the synergy of concurrent multi-spectral multiple-technique observations from the low-orbit A-Train mission to identify specific signatures in high IWC cloud regions, and finally develop a satellite-based nowcasting tool to track and monitor convective systems over the Tropical Atlantic. The paper presents the HAIC SP3 objectives and provides an objective status of the sub-project at mid term of the HAIC project

Retrieval of cloud and aerosol properties from combined IIR, lidar and WFC observations of CALIPSO

International audienceWe present a general overview of the recent advancement in the retrieval of the radiative and microphysical parameters of ice clouds and desert aerosols derived at the global scale from the combination of the Infrared Imaging Radiometer (IIR), Wide Field camera (WFC) and Cloud and Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO platform