Benchmarking the Raw Model-Generated Background Forecast in Rapidly Updated Surface Temperature Analyses. Part I: Stations

High-quality, high-resolution, hourly unbiased surface (2 m) temperature analyses are needed for many applications, including training and validation of statistical postprocessing applications. These temperature analyses are often generated through data assimilation procedures, whereby a background short-range gridded forecast is adjusted to newly available observations. Even with frequent updates to newly available observations, surface-temperature analysis errors and biases can be comparatively large relative to errors and biases of midtropospheric variables, especially over land, despite more near-surface in situ observations. Larger near-surface errors may have several causes, including biased background forecasts and the spatial heterogeneity of surface temperatures that results from subgrid-scale surface, vegetation, land-use, and terrain variations. Are biased raw background forecasts the predominant cause of surface temperature analysis errors? Part I of this two-part series describes a simple benchmark for evaluating the error characteristics of short-term (1 h) raw model background surface temperature forecasts. For stations with a relatively complete time series of data, it is possible to generate an hourly, diurnally, and seasonally dependent observation climatology at a station. The deviation of the current hour’s temperature observation with respect to this hour’s and Julian day’s climatology is added to the climatology for the next hour. For contiguous U.S. stations in July 2015, the station benchmark was lower in error than interpolated 1-h high-resolution numerical predictions of surface temperature from NOAA’s High-Resolution Rapid Refresh (HRRR) system, although not including full postprocessing. For August 2018, 1-h HRRR forecasts were much improved when tested against the station benchmark.

Cold trapped - Correcting locomotion dependent observation biases in thermal preference of Drosophila

Sensing environmental temperatures is essential for the survival of ectothermic organisms. In Drosophila, two methodologies are used to study temperature preferences (TP) and the genes involved in thermosensation: two-choice assays and temperature gradients. Whereas two-choice assays reveal a relative TP, temperature gradients can identify the absolute Tp. One drawback of gradients is that small ectothermic animals are susceptible to cold-trapping: a physiological inability to move at the cold area of the gradient. Often cold-trapping cannot be avoided, biasing the resulting TP to lower temperatures. Two mathematical models were previously developed to correct for cold-trapping. These models, however, focus on group behaviour which can lead to overestimation of cold-trapping due to group aggregation. Here we present a mathematical model that estimates the behaviour of individual Drosophilain temperature gradients. The model takes the spatial dimension and temperature difference of the gradient into account, as well as the rearing temperature of the flies. Furthermore, it allows quantifying cold-trapping, reveals true TP, and differentiates between temperature preference and tolerance. Online simulation is hosted at http://igloo.uni-goettingen.de. The code can be accessed at https://github.com/zerotonin/igloo.

HARDWARE-SOFTWARE COMPLEX FOR TESTING OF BEHIND-THE-HORIZON RADAR STATIONS USING THE METHOD OF AUTOMATIC PASSIVE AIRSPACE SURVEILLANCE

The basis of the work of over-horizon radar stations is a jump mechanism of propagation of short-range radio waves, which involves the adaptation of the equipment to continuously changing geophysical and noise conditions. The review of the station’s area of responsibility is usually carried out sequentially at a number of frequencies. To assess the probability of correct detection of air objects and other characteristics of over-horizon radar stations, a comprehensive test simulation stand and an algorithm for assessing the current combat capabilities are used. A comprehensive simulation test stand to test and confirm compliance with the achieved characteristics of the station simulates different variants of the air situation in the field of view of the radar. It is proposed to use the technology to obtain the parameters of the routes of scheduled aircraft, which are equipped with dependent observation equipment, compare them automatically with the parameters of the finally detected route of the station and to evaluate the characteristics of over-horizon radar in real helio and geophysical conditions. Thus, the hardware and software complex for testing over-horizon stations for flight air objects using the method of automatic passive review of airspace, including outside the territory of the Russian Federation will allow to evaluate their tactical and technical characteristics in automatic mode, in real conditions of application.