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The South China Sea Monsoon Experiment (SCSMEX) is an international field experiment with the objective to better understand the key physical processes for the onset and evolution of the summer monsoon over Southeast Asia and southern China aiming at improving monsoon predictions. In this article, a description of the major meteorological observation platforms during the intensive observing periods of SCSMEX is presented. In addition, highlights of early results and discussions of the role of SCSMEX in providing valuable in situ data for calibration of satellite rainfall estimates from the Tropical Rainfall Measuring Mission are provided. Preliminary results indicate that there are distinctive stages in the onset of the South China Sea monsoon including possibly strong influences from extratropical systems as well as from convection over the Indian Ocean and the Bay of Bengal. There is some tantalizing evidence of complex interactions between the supercloud cluster development over the Indian Ocean, advancing southwest monsoon flow over the South China Sea, midlatitude disturbances, and the western Pacific subtropical high, possibly contributing to the disastrous flood of the Yangtze River Basin in China during June 1998.

To understand how the brain processes sensory information to guide behavior, we must know how stimulus representations are transformed throughout the visual cortex. Here we report an open, large-scale physiological survey of activity in the awake mouse visual cortex: the Allen Brain Observatory Visual Coding dataset. This publicly available dataset includes the cortical activity of nearly 60,000 neurons from six visual areas, four layers, and 12 transgenic mouse lines in a total of 243 adult mice, in response to a systematic set of visual stimuli. We classify neurons on the basis of joint reliabilities to multiple stimuli and validate this functional classification with models of visual responses. While most classes are characterized by responses to specific subsets of the stimuli, the largest class is not reliably responsive to any of the stimuli and becomes progressively larger in higher visual areas. These classes reveal a functional organization wherein putative dorsal areas show specialization for visual motion signals.

An extensive application of a rainy profiling algorithm (ZPHI) employing a C-band polarimetric radar (the C-POL radar of the Australian Bureau of Meteorology Research Centre in Darwin) is presented. ZPHI belongs to the class of rain profiling algorithms that have been developed for spaceborne or airborne radars operating at attentuating frequencies.

The scientific mission of the Project MindScope is to understand neocortex, the part of the mammalian brain that gives rise to perception, memory, intelligence, and consciousness. We seek to quantitatively evaluate the hypothesis that neocortex is a relatively homogeneous tissue, with smaller functional modules that perform a common computational function replicated across regions. We here focus on the mouse as a mammalian model organism with genetics, physiology, and behavior that can be readily studied and manipulated in the laboratory. We seek to describe the operation of cortical circuitry at the computational level by comprehensively cataloging and characterizing its cellular building blocks along with their dynamics and their cell type-specific connectivities. The project is also building large-scale experimental platforms (i.e., brain observatories) to record the activity of large populations of cortical neurons in behaving mice subject to visual stimuli. A primary goal is to understand the series of operations from visual input in the retina to behavior by observing and modeling the physical transformations of signals in the corticothalamic system. We here focus on the contribution that computer modeling and theory make to this long-term effort.

The Island Thunderstorm Experiment (ITEX) is a field and modeling study of the tropical thunderstorms that form regularly over Bathurst and Melville Islands north of Darwin, Northern Territory, Australia, during the transition season and breaks in the summer monsoon season. Such thunderstorms are of widespread occurrence in the tropics and they play an important role in tropical dynamics. ITEX is a joint project of the Bureau of Meteorology Research Centre and Monash University's Centre for Dynamical Meteorology. Preliminary studies have been used to plan an intensive period of observations that was carried out from 20 November to 10 December 1988. The resulting data will provide the basis for a series of analytical and numerical studies of tropical island thunderstorms.

Disdrometer data measured during the passage of tropical continental squall lines in Darwin, Australia, are analyzed to study characteristics of raindrop size distribution (DSD). Fifteen continental squall lines were selected for the DSD analysis. An observed squall line was partitioned into three regions based on radar reflectivity pattern, namely, convective line, stratiform, and reflectivity trough. A convective line was further partitioned into the convective center, leading edge, and trailing edge using a threshold rain rate of 20 mm h−1. Statistics of modified gamma DSD parameters obtained by a least squares fitting method show distinct differences between the convective-center and the stratiform regions; the shape of DSD for the convective center is convex upward, but it is more exponential for the stratiform region; the intercept parameterN₀ of the modified gamma function for the convective center and the reflectivity trough tends to be larger than that for the stratiform region, also. The observed drop size distributions are normalized to remove the effect of differences in rainfall rate. Gamma distributions then are least squares fitted to the normalized DSD data to show distinct differences between the convective-center and the stratiform regions; the characteristics of the trailing-edge and reflectivity-trough regions are equivalent to those of the convective center. DSD changes associated with the rainwater content variations are calculated using the obtained normalized gamma DSD function and the observedD₀–Mrelationship. The simulation demonstrates that the stratiform region is characterized by a larger drop spectrum (i.e., the maximum drop diameter and the median volume diameter are larger for the stratiform region than the convective center and the reflectivity trough for DSD with the same rainwater content). The Waldvogel ‘‘N₀ jump’’ is clearly shown, and the large drop spectrum for the stratiform region suggests the importance of the aggregation mechanism above the melting level in the stratiform region. The difference in the DSD for the convective-center and the stratiform regions causes systematic differences inZ–Rrelationships (Z=ARb ). A larger value for coefficientAin the stratiform region is found, but values ofAandbchange case by case; an inverse relationship betweenAandb(A= 103.22 b −6.25) is found for rainfall in the convective-center and the trailing-edge regions.

One of the main goals of the Sydney 2000 Forecast Demonstration Project was to demonstrate the efficacy and utility of automated severe weather detection radar algorithm. Joe et al describe the radar-based severe weather algorithm used in the project, their performance, and related radar issues. The radar algorithms attempt to diagnose the presence of storm cells, provide storm tracks, identify mesocyclone circulations, downburst and/or microburst and hail, and provide storm ranking.

A propagation correction algorithm utilizing the differential propagation phase (ϕ dp) was developed and tested on C-band polarimetric radar observations of tropical convection obtained during the Maritime Continent Thunderstorm Experiment. An empirical procedure was refined to estimate the mean coefficient of proportionalitya(b) in the linear relationship betweenϕ dpand the horizontal (differential) attenuation throughout each radar volume. The empirical estimates of these coefficients were a factor of 1.5–2 times larger than predicted by prior scattering simulations. This discrepancy was attributed to the routine presence of large drops [e.g., differential reflectivityZ dr≥ 3 dB] within the tropical convection that were not included in prior theoretical studies. Scattering simulations demonstrated that the coefficientsaandbare nearly constant for small to moderate sized drops (e.g., 0.5 ≤Z dr≤ 2 dB; 1 ≤ diameterD₀ < 2.5 mm) but actually increase with the differential reflectivity for drop size distributions characterized byZ dr> 2 dB. As a result, large drops 1) bias the mean coefficients upward and 2) increase the standard error associated with the mean empirical coefficients down range of convective cores that contain large drops. To reduce this error, the authors implemented a \"large drop correction\" that utilizes enhanced coefficientsa* andb* in large drop cores. Validation of the propagation correction algorithm was accomplished with cumulative rain gauge data and internal consistency among the polarimetric variables. The bias and standard error of the cumulative radar rainfall estimatorR(Zh ) [R(K dp,Z dr)], whereZh is horizontal reflectivity andK dpis specific differential phase, were substantially reduced after the application of the attenuation (differential attenuation) correction procedure utilizingϕ dp. Similarly, scatterplots of uncorrectedZh (Z dr) versusK dpsubstantially underestimated theoretical expectations. After application of the propagation correction algorithm, the bias present in observations of bothZh (K dp) andZ dr(K dp) was removed and the standard errors relative to scattering simulation results were significantly reduced.