2019. április 26. péntek

Vol. 118, No. 1 * Pages 1–92 * Januar - March 2014

Quarterly journal of the Hungarian Meteorological Service

Risk analysis of the first and last frost occurrences during growing season of vegetables in the Elbe River lowland
Vera Potop, Pavel Zahradniček, Luboš Türkott, Petr Štěpánek, and Josef Soukup
 PDF (631 KB)   |   Abstract

This study has, for the first time, analyzed in detail the risk occurrences of the last spring frost, first fall frost, and the length of the frost-free period during the growing season of vegetable crops at a high horizontal resolution of 10 km (CZGRIDS, ALADIN-Climate/CZ) in the Elbe River lowland. The daily minimum air temperature from 116 grid points throughout the studied area for the period 1961–2011 was used. The daily values of minimum air temperature ranges of 0 °C to −1.1 °C, −1.2°C to −2.2 °C, and below −2.2 °C were considered to constitute mild, moderate, and severe frosts intensities, respectively. Firstly, comprehensive analysis of the spatio-temporal variability of the date of the last spring frost, the date of the first fall frost, and the length of the frost-free period in the Elbe River lowland were provided. Secondly, a catalogue of the mean dates of the spring and fall frosts for the three frost severities (mild, moderate, and severe) and degrees of earliness (early, mean, and late ending/beginning), as well as the length of the frost-free period over the Elbe River lowland, was developed. Thirdly, to identify the areas with high-risk occurrences of damaging last spring frosts during the sowing/planting period of vegetables in the Elbe River Lowland.
According to the regional catalogue of frosts, an earlier ending of spring and a later beginning of fall frosts, simultaneous with the latest ending of the frost-free period, were recorded during the 1990s, 2000s, and 2010s. The severe spring frosts in the period of 1981–2011 ended earlier than in the period of 1961–1980; consequently, the end of the 20th and the beginning of the 21st century are suitable periods for the growth extension of species and varieties of vegetables with longer growing seasons and higher demands on temperature. Whereas the latest spring frost has ended on an earlier date across the Elbe lowland, the first frost date in the fall has generally been delayed to a later date.

Seasonality and geographical occurrence of West Nile fever and distribution of Asian tiger mosquito
Attila Trájer, Ákos Bede-Fazekas, János Bobvos, and Anna Páldy
 PDF (907 KB)   |   Abstract

The importance and risk of emerging mosquito borne diseases is going to increase in the European temperate areas due to climate change. The present and upcoming climates of Transdanubia seem to be suitable for the main vector of Chikungunya virus, the Asian tiger mosquito, Aedes albopictus Skuse (syn. Stegomyia albopicta). West Nile fever is recently endemic in Hungary. We used climate envelope modeling to predict the recent and future potential distribution/occurrence areas of the vector and the disease. We found that climate can be sufficient to explain the recently observed area of A. albopictus, while in the case of West Nile fever, the migration routes of reservoir birds, the run of the floodplains, and the position of lakes are also important determinants of the observed occurrence.

Impact of climate change on the potential distribution of Mediterranean pines
Ákos Bede-Fazekas, Levente Horváth, Márton Kocsis
 PDF (822 KB)   |   Abstract

The impact of climate change on the potential distribution of four Mediterranean pine species – Pinus brutia Ten., Pinus halepensis Mill., Pinus pinaster Aiton, and Pinus pinea L. – was studied by the Climate Envelope Model (CEM) to examine whether these species are suitable for the use as ornamental plants without frost protection in the Carpathian Basin. The model was supported by EUFORGEN digital area database (distribution maps), ESRI ArcGIS 10 software’s Spatial Analyst module (modeling environment), PAST (calibration of the model with statistical method), and REMO regional climate model (climatic data). The climate data were available in a 25 km resolution grid for the reference period (1961–1990) and two future periods (2011–2040, 2041–2070). The regional climate model was based on the IPCC SRES A1B scenario. While the potential distribution of P. brutia was not predicted to expand remarkably, an explicit shift of the distribution of the other three species was shown. Northwestern African distribution segments seem to become abandoned in the future. Current distribution of P. brutia may be highly endangered by the climate change. P. halepensis in the southern part and P. pinaster in the western part of the Carpathian Basin may find suitable climatic conditions in the period of 2041–2070.

Sensitivity analysis of microscale obstacle resolving models for an idealized Central European city center, Michel-Stadt
Anikó Rákai, Gergely Kristóf, and Jörg Franke
 PDF (1921 KB)   |   Abstract

Microscale meteorological models with obstacle resolving grids are an important part of air quality and emergency response models in urban areas providing the flow field for the dispersion model. The buildings as bluff bodies are challenging from the discretization point of view and have an effect on the quality of the results. In engineering communities the same topic has emerged, called computational wind engineering (CWE), using the methods of computational fluid dynamics (CFD) calculating wind load on buildings, wind comfort in the urban canopy, and pollutant dispersion. The goal of this paper is to investigate the sensitivity of this method to the discretization procedure used to resolve the urban canopy with meshes which are of operational size, i.e., which can be run on a single powerful computer of a design office as well. To assess the quality of the results, the computed mean and rms (root mean square) velocity components are compared to detailed wind tunnel results of an idealized Central European city center, Michel-Stadt. A numerical experiment is carried out where the numerical sensitivity of the solution is tested by additional solutions on different grid resolutions (at least 3 stages of grid refinement), unrelated grid types (tetrahedral, polyhedral, Cartesian hexahedral, and body fitted hexahedral, all automatically generated), and different discretization schemes. For an objective qualitative judgment two metrics are investigated, the well know hit rate and another metric that does not depend on threshold values. The quality of the meshes is investigated with correspondence to the numerical stability, CPU-time need, and grid quality metric. It is shown that the solution with the best resulting metric is not necessarily the most suitable for operational purposes and almost 20% difference in the hit rate metric can result from different discretization approaches.

Facts about the use of agrometeorological information in Hungary and suggestions for making that more efficient
Zoltán Varga
 PDF (239 KB)   |   Abstract

Demands on use of information upon relationship between meteorological conditions and agricultural production were from the beginning of meteorology and from the beginning of human civilization. The sudden development of natural sciences during the 19th and 20th centuries opened up a new prospect in producing meteorological information which was of use to food processing. On the other hand, contemporary agricultural development needed supply of more detailed and more practical agrometeorological information. Increasing importance of ecological agriculture at the expense of intensive farming systems and uncertain effects of climate change did not reduce the want for agrometeorological information; in fact, they extended the needs for those in the last decades. But positive tendencies of domestic agrometeorological research and information service in the second half of the 20th century declined till the 1990s, and there is no reason to be optimistic on the grounds of current situation.
This work attempts to review not only possibilities and results of agrometeorological information supply, but also interdisciplinary factors, such as factors of economical development and regulation, education, agricultural-advisory system, etc., which set back the development of this area. The base of our investigations is a SWOT analysis which is a strategic planning method of economical sciences used to evaluate strengths, weaknesses, opportunities, and threats involved in a project. This way we try to answer the following questions:
- Why is agrometeorology no longer an important economical factor in Hungary?
- How could we make agrometeorological research and information service become a productive economical factor again?