[1] A method for discriminating cloud particle types was developed using lidar backscattering copolarization and cross-polarization channel measurements from Cloud-Aerosol Lidar With Orthogonal Polarization (CALIOP) on board Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO). In spaceborne lidar measurements, significant multiple scattering effects discriminate between cloud water and ice difficult using the depolarization ratio (d). We theoretically estimated the relationship between d and cloud extinction on the basis of the backward Monte Carlo method. Cloud particle type was determined by the combined use of d and the ratio of attenuated backscattering coefficients for two vertically consecutive layers. Ice particles were further classified into two categories: randomly oriented ice crystals (3-D ice) and horizontally oriented plates (2-D plate). The method was applied to CALIOP data for September-November 2006. We found that 3-D ice generally occurred colder than −20°C, whereas 2-D plate occurred between −10°C and −20°C, with high-occurrence frequency in high-latitude regions. We compared the results to those obtained using the vertical feature mask (VFM). The VFM tended to show a homogeneous cloud type through the entire cloud layer in vertical directions and misclassified 2-D plate as water. The ratio of water particles relative to ice particles decreased with decreasing temperature. By the proposed method, water cloud occurrence in subtropical and high-latitude regions was greater (up to 20%) than in the other regions below −10°C; however, the VFM results did not show such dependence on latitude. Comparison of ice and water cloud between our results and Moderate Resolution Imaging Spectroradiometer (MODIS) products showed better agreement for water cloud than for ice cloud.Citation: Yoshida, R., H. Okamoto, Y. Hagihara, and H. Ishimoto (2010), Global analysis of cloud phase and ice crystal orientation from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data using attenuated backscattering and depolarization ratio,
[1] We developed a cloud mask scheme that combines measurements from CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellites. First, we developed a cloud mask scheme for CALIPSO using a threshold of the attenuated total backscattering coefficient and a spatial continuity test. We then developed a combined CloudSat-CALIPSO cloud mask. These cloud masks were applied to 3 months of data from September to November 2006, and the vertical distributions of zonal mean cloud fractions and cloud coverage were analyzed. We also examined the standard vertical feature mask (VFM) cloud scheme. The VFM occasionally made false detections because of its horizontal averaging procedure and seemed to misclassify noise or aerosols as clouds. In addition, the VFM appeared to significantly overestimate low-level clouds. Below 2 km, the cloud fraction differed by as much as 25% between the VFM and our combined scheme. We also compared the zonal mean cloud coverage for the topmost layer detected by the sensors using our CALIPSO scheme, the VFM, our combined CloudSat-CALIPSO scheme, and the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) results. For low-level clouds (>680 hPa), the MODIS result was larger than that of our CloudSat-CALIPSO scheme, and results from the VFM and our CALIPSO scheme differed by as much as 15%. The CALIPSO, CloudSat-CALIPSO, and MODIS results were similar for total cloud coverage, but the VFM result was different. Because of possible misclassification at low levels, the VFM showed the largest cloud coverage in middle and low latitudes.Citation: Hagihara, Y., H. Okamoto, and R. Yoshida (2010), Development of a combined CloudSat-CALIPSO cloud mask to show global cloud distribution,
[1] We describe a method to evaluate cloud microphysics simulated with a global cloud-resolving model against CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite data. Output from the Nonhydrostatic Icosahedral Atmospheric Model (NICAM) is run through a satellite-sensor simulator (Joint Simulator for Satellite Sensors), then directly compared to the radar and lidar signals from CloudSat and CALIPSO. The forward approach allows for consistency in cloud microphysical assumption involved in the evaluation. To investigate the dependence of the signals on the temperature, we use temperature extensively as the vertical coordinate. The global statistical analysis of the radar reflectivity shows that the simulation overestimates all the percentiles above À50°C and that snow category contributes significantly to low reflectivity values between À80 and À40°C. The simulated lidar signals have two modes associated with cloud ice and snow categories, though the observations have only one mode. The synergetic use of radar reflectivity and lidar backscatter enables us to determine the relative magnitudes of ice/liquid water contents and effective radii without use of retrievals. The radar-and-lidar diagnosis for cloud tops shows that, due to snow category, NICAM overestimates the mass-equivalent effective radius and underestimates ice water content. Also, the diagnosis was shown to be useful to investigate sensitivities of the parameters of bulk microphysical schemes on the water contents and sizes. The nonspherical scattering of ice particles was shown to affect the above radar-and-lidar diagnosis for large reflectivity ranges but not to alter most of the other diagnoses for this simulation.
[1] We developed a new radar-lidar algorithm that can be applied to CloudSat and CloudAerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data to retrieve ice microphysics. The algorithm analyzes the specular reflection of lidar signals often observed by CALIPSO with large backscattering coefficients and small depolarization ratios. Analyses of CloudSat and CALIPSO data by our former radar-lidar algorithm showed problems retrieving ice cloud microphysics when specular reflection was present. We implemented additional look-up tables for horizontally oriented plates. A specular reflection mode in the radar-lidar algorithm could drastically improve retrieval results. The new radar-lidar algorithm requires depolarization ratios measured by CALIPSO, in addition to the radar reflectivity factor and backscattering coefficient at 532 nm. We performed several sensitivity studies to retrieval results. Nonsphericity turned out to be the largest source of uncertainties. Global analyses of ice microphysics for CloudSat-CALIPSO overlap regions were performed. The effective radius decreased as the altitude increased. The effective radius in the specular reflection ranged from 100 to 300 mm. The ice water content (IWC) ranged from 10 −4 to several tenths of a gram per cubic meter. Both effective radius and IWC increased as the altitude (temperature) decreased (increased). The largest mixing ratio of oriented particles occurred between −20 and −5°C. The IWC had two maxima in the tropics above 15 km and around 5 km. We also examined the differences in ice microphysics over land and ocean. The effective radius was similar over land and ocean, but the IWC tended to be larger over land.
We compare the cloud detection and cloud phase determination of three independent climatologies based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) to airborne in situ measurements. Our analysis of the cloud detection shows that the differences between the satellite and in situ measurements mainly arise from three factors. First, averaging CALIPSO Level l data along track before cloud detection increases the estimate of high-and low-level cloud fractions. Second, the vertical averaging of Level 1 data before cloud detection tends to artificially increase the cloud vertical extent. Third, the differences in classification of fully attenuated pixels among the CALIPSO climatologies lead to differences in the low-level Arctic cloud fractions. In another section, we compare the cloudy pixels detected by colocated in situ and satellite observations to study the cloud phase determination. At midlatitudes, retrievals of homogeneous high ice clouds by CALIPSO data sets are very robust (more than 94.6% of agreement with in situ). In the Arctic, where the cloud phase vertical variability is larger within a 480 m pixel, all climatologies show disagreements with the in situ measurements and CALIPSO-General Circulation Models-Oriented Cloud Product (GOCCP) report significant undefined-phase clouds, which likely correspond to mixed-phase clouds. In all CALIPSO products, the phase determination is dominated by the cloud top phase. Finally, we use global statistics to demonstrate that main differences between the CALIPSO cloud phase products stem from the cloud detection (horizontal averaging, fully attenuated pixels) rather than the cloud phase determination procedures. 100 km) and have been used recently to emphasize models' flaws [Cesana et al., 2015; Komurcu et al., 2014]. CESANA ET AL. CALIPSO CLOUD PHASE VALIDATION 5788
To trigger gamete fusion, spermatozoa need to activate the molecular machinery in which sperm IZUMO1 and oocyte JUNO (IZUMO1R) interaction plays a critical role in mammals. Although a set of factors involved in this process has recently been identified, no common factor that can function in both vertebrates and invertebrates has yet been reported. Here, we first demonstrate that the evolutionarily conserved factors dendrocyte expressed seven transmembrane protein domain-containing 1 (DCST1) and dendrocyte expressed seven transmembrane protein domain-containing 2 (DCST2) are essential for sperm–egg fusion in mice, as proven by gene disruption and complementation experiments. We also found that the protein stability of another gamete fusion-related sperm factor, SPACA6, is differently regulated by DCST1/2 and IZUMO1. Thus, we suggest that spermatozoa ensure proper fertilization in mammals by integrating various molecular pathways, including an evolutionarily conserved system that has developed as a result of nearly one billion years of evolution.
The thermodynamic hypothesis of protein folding, known as the “Anfinsen’s dogma” states that the native structure of a protein represents a free energy minimum determined by the amino acid sequence. However, inconsistent with the Anfinsen’s dogma, globular proteins can misfold to form amyloid fibrils, which are ordered aggregates associated with diseases such as Alzheimer’s and Parkinson’s diseases. Here, we present a general concept for the link between folding and misfolding. We tested the accessibility of the amyloid state for various proteins upon heating and agitation. Many of them showed Anfinsen-like reversible unfolding upon heating, but formed amyloid fibrils upon agitation at high temperatures. We show that folding and amyloid formation are separated by the supersaturation barrier of a protein. Its breakdown is required to shift the protein to the amyloid pathway. Thus, the breakdown of supersaturation links the Anfinsen’s intramolecular folding universe and the intermolecular misfolding universe.
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