Convection-circulation interactions over West Africa in simulations with explicit and parameterised convection

<p>This work examines the representation of convection-circulation coupling over tropical West Africa in convection-permitting models. Tropical West Africa is not only a region characterised by extremely high-impact weather, in the form of intense and frequent organised convection, but it is also a region of strong baroclinicity and wind shear, and therefore an excellent natural laboratory for examining the connections between mesoscale convection and synoptic circulations. Developing understanding of<sub></sub>convection-circulation coupling is crucial to informing development of convection parameterisations and improving regional forecasts of high-impact weather.</p><p>We evaluate output from the CP4-Africa configuration of the Met Office Unified Model to investigate links between convective activity and synoptic motions. To illustrate its strengths in representing convection-circulation feedbacks, CP4 output is compared to that from a similar UM configuration which uses a convection parameterisation.</p><p>We examine the mean diurnal cycle of circulation during the storm season. Distinct diurnal patterns in circulation tendency are compared to patterns in updraughts and precipitation, which illustrate different forms of convection which can be observed at different points during the day. A “congestus” mode convects up to around the freezing level from morning until early evening, while deep organised convection triggers in the mid-to-late afternoon and persists overnight. The two forms of convection appear to cause characteristically different responses in the synoptic circulation.</p><p>To confirm which physical processes cause changes to circulation in the region, we calculate terms in the circulation tendency equation. Separating these terms into mean and eddy-flux contributions allows us to establish the extent to which mesoscale systems and synoptic structures each influence the diurnal changes to circulation.</p>

Development and Evaluation of a Hydrometeorological Forecasting System Using the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Model

In this study, an experimental hydrometeorological forecasting system was developed based on the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) model. The system downloads global real-time ocean, atmosphere, and wave forcing data, producing regional forecasts every day. A coastal area in South China, encompassing Hainan Island, Leizhou Peninsula, and surrounding sea areas, was chosen as the study domain. A series of 72-hour forecasting simulations were conducted in the area, lasting from July 27 to August 31, 2019. The forecasts throughout August were chosen for evaluation with station observations, along with two sets of reanalysis data, ERA5 and CLDAS. The evaluation results revealed that the COAWST model had high potential for routine forecasting operations. The 24 h forecasts, with a lead time of 24 hours, had high accuracy, while the 48 h and 72 h forecasts did not differ greatly in terms of performance. The distributions of bias between forecast and reanalysis data showed obvious differences between land and sea, with more forecasted precipitation and lower temperatures in land grids than in sea grids. In most cases, the forecasts were closer to ERA5 in terms of means and other statistical measures. The forecasts enlarged the land-sea differences of temperature when compared with ERA5 and strengthened summer monsoon with more moisture transported to land areas. Resulting from that, a forecasted bias of lower surface pressure, higher air humidity, stronger south wind, and so forth was also detected over the domain but at low values.

FACTOR ANALYSIS OF THE CENTRAL BLACK EARTH MACROREGION AREAS ECONOMIC DEVELOPMENT

Effective implementation of regional policy is impossible without assessing the current environment of the region’s functioning, which is formed under the influence of internal factors. Among the many factors that determine the socio-economic development of the region, we have identified: human potential, innovation potential, investment potential, digitalization of the economy, production potential, quality of life and infrastructure development. Each of the selected factors can be characterized by using a system of statistical indicators. In regional forecasts, internal factors act as control parameters, changing them it is possible to find an opportunity to change the course and direction of socio-economic processes in the region. This explains the necessity and relevance of the study. The purpose of this article is to form a set of indicators to assess the factor load on the socio-economic development of the region and determine its vector. The method of factor analysis on an indicative basis was used for achieving this goal. The importance of factorial analysis lies, first of all, in the fact that its results will make it possible to assess the share of influence of each factor on the “level of socio-economic development of the region” and to develop appropriate tools for managing growth factors. Taking into account the formed system of indicators, an analysis of the Central Black Earth macroregion areas economic development was carried out. The greatest factor load on the socio-economic development of the region is exerted by the innovation potential, production potential and human potential of the region. As a result of the study, a matrix of the regions distribution by the level of socio-economic development was built, reflecting the position of the region in dynamics. During the study period, the Voronezh region occupies a leading position, and the Tambov region is an outsider region. In addition, for each region, growth factors and restrictions on the development of the region were identified, which must be taken into account when building regional forecasts.

Comparisons between Sentinel-5P TROPOMI NO2 and the European ensemble air quality forecasts of CAMS

<pre class="moz-quote-pre">In our contribution we present comparisons between TROPOMI observations of NO2 (nitrogen dioxide) and the CAMS regional forecasts and analyses for Europe. The Sentinel-5P TROPOMI instrument, launched in October 2017, provides unique observations of atmospheric trace gases at a high resolution of about 5 km, resolving individual point sources, medium-scale towns, roads and shipping routes. The datasets have a global daily coverage, but these datasets are especially well suited to test high-resolution regional-scale air quality models and provide valuable input for emission inversion systems. In Europe, the Copernicus Atmosphere Monitoring Service (CAMS) has implemented a regional air quality forecasting capability for Europe based on an ensemble of 7-9 European models, available at a resolution of 0.1x0.1 degree. <br />We discuss the different ways of making these comparisons, and present the quantitative results for summer and winter months and individual days. The models generally capture the fine-scale daily and averaged features observed by TROPOMI in much detail. We show that replacing the global 1x1 degree a-priori information in the retrieval by the regional 0.1x0.1 degree profiles of CAMS leads to significant changes (increases at hotspot emission locations) in the TROPOMI retrieved tropospheric column. Apart from comparing with the ensemble model, we also present the results for the individual CAMS models. </pre>

Benchmark seasonal prediction skill estimates based on regional indices

Basic statistical metrics such as autocorrelations and across-region lag correlations of sea ice variations provide benchmarks for the assessments of forecast skill achieved by other methods such as more sophisticated statistical formulations, numerical models, and heuristic approaches. In this study we use observational data to evaluate the contribution of the trend to the skill of persistence-based statistical forecasts of monthly and seasonal ice extent on the pan-Arctic and regional scales. We focus on the Beaufort Sea for which the Barnett Severity Index provides a metric of historical variations in ice conditions over the summer shipping season. The variance about the trend line differs little among various methods of detrending (piecewise linear, quadratic, cubic, exponential). Application of the piecewise linear trend calculation indicates an acceleration of the winter and summer trends during the 1990s. Persistence-based statistical forecasts of the Barnett Severity Index as well as September pan-Arctic ice extent show significant statistical skill out to several seasons when the data include the trend. However, this apparent skill largely vanishes when the data are detrended. In only a few regions does September ice extent correlate significantly with antecedent ice anomalies in the same region more than 2 months earlier. The springtime “predictability barrier” in regional forecasts based on persistence of ice extent anomalies is not reduced by the inclusion of several decades of pre-satellite data. No region shows significant correlation with the detrended September pan-Arctic ice extent at lead times greater than a month or two; the concurrent correlations are strongest with the East Siberian Sea. The Beaufort Sea's ice extent as far back as July explains about 20 % of the variance of the Barnett Severity Index, which is primarily a September metric. The Chukchi Sea is the only other region showing a significant association with the Barnett Severity Index, although only at a lead time of a month or two.

Comparison of Simulated Precipitation over East Asia in Two Regional Models with Hydrostatic and Nonhydrostatic Dynamical Cores

This study examines the characteristics of a nonhydrostatic dynamical core compared to a corresponding hydrostatic dynamical core in the Regional Model Program (RMP) of the Global/Regional Integrated Model system (GRIMs), a spectral model for regional forecasts, focusing on simulated precipitation over Korea. This kind of comparison is also executed in the Weather Research and Forecasting (WRF) finite-difference model with the same physics package used in the RMP. Overall, it is found that the nonhydrostatic dynamical core experiment accurately reproduces the heavy rainfall near Seoul, South Korea, on a 3-km grid, relative to the results from the hydrostatic dynamical core in both models. However, the characteristics of nonhydrostatic effects on the simulated precipitation differ between the RMP and WRF Model. The RMP with the nonhydrostatic dynamical core improves the local maximum, which is exaggerated in the hydrostatic simulation. The hydrostatic simulation of the WRF Model displaces the major precipitation area toward the mountainous region along the east coast of the peninsula, which is shifted into the observed area in the nonhydrostatic simulation. In the simulation of a summer monsoonal rainfall, these nonhydrostatic effects are negligible in the RMP, but the simulated monsoonal rainfall is still influenced by the dynamical core in the WRF Model even at a 27-km grid spacing. One of the reasons for the smaller dynamical core effect in the RMP seems to be the relatively strong horizontal diffusion, resulting in a smaller grid size of the hydrostatic limit.