Explore the vast range of titles available.

A multi-model ensemble of 15 climate change projections from regional climate models was used to assess the impact of changes in air temperature and precipitation on the phenology of pest species in agriculture. This allowed the bandwidths of expected changes in both meteorological variables to be calculated, forming the basis for assessing and clearly communicating the uncertainties related to the model results. More specifically, we investigated the potential impact of regional climate change effects on the crop invasion of the rape stem weevil, Ceutorhynchus napi Gyllenhal (Coleoptera: Curculionidae), in Central Europe (Luxembourg). Multisite and perennial data from field observations were used to choose a biological model from the literature, based on daily maximum air temperature and daily totals of precipitation to describe the migration of C. napi. Based on this statistical relation, we were able to reproduce the observed crop invasion with a mean root mean squared error (RMSE) of 10 days. Daily values of projected maximum air temperatures and daily totals of precipitation of the multi-model ensemble were used as input data for the threshold-based biological model that projects the immigration of this pest species into oilseed rape crops (Brassica napus L.). We examined three thirty-year timespans, the near (2021 to 2050) and the far future (2069 to 2098) and compared them to a reference timespan (1961 to 1990). The projections showed a significant shift of crop invasion to an earlier onset for the near (14 days) and far future (21 days) compared to the reference period. In addition, the timespan in which the potential crop invasion will take place increased from 53 days in the reference timespan to 73 days in the near and 65 days in the far future based on the ensemble median values. It could be expected that a shifting of the immigration period will increase the risk of missing the appropriate time frame for an insecticide application. A depletion of stored nutrient resources, leading to starvation after diapause, can be eliminated for C. napi under climate change effects, as this species hibernates motionless as an adult in earth cocoons until emergence in early springtime driven by temperature.

Forests occupy one third of the world’s land area and govern carbon (C) transfers and influence nitrogen (N) content in the biosphere. Afforestation leads to soil changes of specific dynamics, often accompanied by acidification. Especially at higher altitudes this effect is accelerated and increased with the stand age since forestation. The change in soil C and N content following afforestation is controlled by a number of factors, including: previous land use (grasslands, cropland, etc.), tree species, soil cultivation method, soil properties (clay content, pH), stand age, site management, topography, and climate. In the Czech Republic, large area changes in land use took place in the last centuries – forests covering roughly 20% in the 18th century currently occupy almost 34%, with still increasing tendencies. This paper compares basic soil properties (soil reaction, total soil organic carbon as well as total nitrogen contents) of the agricultural land and land afforested 40–60 years ago. The results confirmed the key role of afforestation in the change of soil organic matter dynamics after establishing new forests on the former agricultural lands in the uppermost mineral soil part of the Orlické hory Mts. region in the Czech Republic. During that time, comparatively substantial changes in soil organic matter and nitrogen were registered. Afforestation considerably increased organic matter content in the studied A-horizons of different land use types. Soil development resulted in a high production of C and N pools under the forest stands, contrary to agricultural land. In general, afforestation caused significant soil acidification. The common tendency of higher acidity of forest soils compared to agricultural ones was documented in the studied case as well. The general tendencies of soil reaction and soil organic matter dynamics at the studied sites are comparable to those in other regions of the Czech Republic.

The physiological response of terrestrial vegetation when directly exposed to an increase in atmospheric carbon dioxide (CO2) concentration could result in warming over the continents in addition to that due to the conventional CO2 \"greenhouse effect.\" Results from a coupled biosphere-atmosphere model (SiB2-GCM) indicate that, for doubled CO2 conditions, evapotranspiration will drop and air temperature will increase over the tropical continents, amplifying the changes resulting from atmospheric radiative effects. The range of responses in surface air temperature and terrestrial carbon uptake due to increased CO2 are projected to be inversely related in the tropics year-round and inversely related during the growing season elsewhere.

We measure the economic impact of climate on land prices. Using cross-sectional data on climate, farmland prices, and other economic and geophysical data for almost 3,000 counties in the United States, we find that higher temperatures in all seasons except autumn reduce average farm values, while more precipitation outside of autumn increases farm values. Applying the model to a global-warming scenario shows a significantly lower estimated impact of global warming on U.S. agriculture than the traditional production-function approach and, in one case, suggests that, even without CO2 fertilization, global warming may have economic benefits for agriculture.

A long time series of monthly soil moisture data during the period of 1931-1993 over the entire U.S. continent has been created with a one-layer soil moisture model. The model is based on the water budget in the soil and uses monthly temperature and monthly precipitation as input. The data are for 344 U.S. climate divisions during the period of 1931-1993. The main goals of this paper are 1) to improve our understanding of soil moisture and its effects on the atmosphere and 2) to apply the calculated soil moisture toward long-range temperature forecasts. In this study, the model parameters are estimated using observed precipitation, temperature, and runoff in Oklahoma (1960-1989) and applied to the entire United States. The comparison with the 8-yr (1984-1991) observed soil moisture in Illinois indicates that the model gives a reasonable simulation of soil moisture with both climatology and interannual variability. The analyses of the calculated soil moisture show that the climatological soil moisture is high in the east and low in the west (except the West Coast), which is determined by the climatological precipitation amounts. The annual cycle of soil moisture, however, is determined largely by evaporation. Anomalies in soil moisture are driven by precipitation anomalies, but their timescales are to first order determined by both climatological temperature (through evaporation) and climatological precipitation. The soil moisture anomaly persistence is higher where normal temperature and precipitation are low, which is the case in the west in summer. The spatial scale of soil moisture anomalies has been analyzed and found to be larger than that of precipitation but smaller than that of temperature. Authors found that generally in the U.S. evaporation anomalies are much smaller in magnitude than precipitation anomalies. Furthermore, observed and calculated soil moisture anomalies have a broad frequency distribution but not the strongly bimodal distribution indicative

The contents of major S-alk(en)ylcysteine sulfoxides (namely alliin, methiin and isoalliin) were determined in a set of 58 various garlic genotypes (22 flowering plant morphotypes, 14 semi bolting plants and 22 scape absent morphotype plants). The plants were cultivated in four successive years (2005-2008) and analysed immediately after harvest and subsequently after eight weeks of storage at 5 deg C. The total content of the three cysteine derivatives in fresh samples varied between 3.35 mg/g fresh weight and 12.77 mg/g fresh weight, with the mean of 7.50 mg/g fresh weight and the average relative proportions of alliin/methiin/isoalliin of 83/16/1. Upon 8-week storage, the average total amount of S-alk(en)ylcysteine sulfoxides increased by 30% to 9.75 mg/g fresh weight, with the alliin/methiin/isoalliin ratio changing to 82/14/4. The data obtained were statistically evaluated using linear discrimination analysis to distinguish the differences between the years of harvest, between freshly harvested and stored samples, and between the individual morphotypes. While the year-to-year differences between the samples were statistically not very significant, the fresh and stored samples as well as the individual garlic morphotypes differed considerably. Our results indicate that the content of S-alk(en)ylcysteine sulfoxides primarily depends on various genetic factors and post-harvest storage conditions, whereas the climatic conditions during the growth (e.g. temperature, irrigation) influence their level to a lesser extent.

The western United States is characterized by complex seasonal precipitation regimes due to the hierarchy of climatic controls that operate at different spatial scales. A climatology of month to month changes in precipitation, using data from 4027 stations, illustrates how different climatic controls govern the annual cycle of precipitation response and explains the spatial distribution of the seasonal precipitation maximum. These results particularly indicate that smaller-scale climatic controls must be considered along with larger-scale ones in order to explain patterns of spatial climate heterogeneity over mountainous areas. The examination of seasonal precipitation maxima during years characterized by abnormally low winter Pacific-North American teleconnection (PNA) patterns and abnormally strong summer monsoons reveal few changes spatially as compared to normal. The lack of changes illustrate that spatial heterogeneity of precipitation seasonality is the rule rather than the exception for much of the mountainous West. The results of this study offer important implications for scholars interested in assessing spatial climatic variations of the western United States at timescales ranging from inter-annual to the late-quaternary

Satellite data and ground rainfall measurements have been used to study variations in the size of the Sahara Desert from 1980 to 1997. Through a combination of the satellite and ground data, the 200 mm yr-1precipitation boundary was mapped for the Saharan-Sahelian region by year. Although highly significant year-to-year variation in the size of the Sahara Desert has occurred, no systematically increasing or decreasing trend from 1980 to 1997 was evident. The area of the Sahara Desert varied from 9 980 000 km2in 1984 to km2in 8 600 000 1994 and had an average 1980-1997 area of 9 150 000 km2.

The variability of extremely heavy precipitation events with duration of 120 min occurring in the area of Cracow, southern Poland was assessed. The analysis was performed using time series of maximum annual precipitation events with durations t = 5, 10, 15, 30, 60, and 120 min, recorded at the Botanical Garden station at the Jagiellonian University in the period of 1906–1990. The periodicity of precipitation was analyzed using the autocorrelation function and Fourier spectral density analysis. The Probable Maximum Precipitation (PMP) was calculated by Hershfield’s statistical method. The analysis of the autocorrelation function of sequences and the Fourier spectral density revealed a clear periodicity of the maximum precipitation. For precipitation with t = 60 min, the maximum values occur every 9 years, but also shorter periods (3-year) may be observed. The PMP values calculated for Cracow differ significantly from the values calculated using the probability distribution, as well as from the ones observed and they increase with increasing precipitation duration. The differences between the PMP and probable as well as observed precipitation tend to decrease with increasing duration of precipitation.

Climatological forecast scenarios for the territory of the Czech Republic assume that possible global climate changes caused by rising greenhouse gas content in the earth's atmosphere due to the burning of fossil fuels would result in an average temperature rise by 1-2 deg C. An appropriate spatial framework to assess the effects of possible climate changes on growth conditions of agricultural crops are the vegetation zones. Vegetation zoning expresses the dependence of biota on the long-term effects of altitude and exposure climate, given by the average as well as extreme air temperatures and the amount and distribution of precipitation (including horizontal precipitation). Climate change is reflected in the gradual shift of vegetation zones to higher altitudes, i.e. by the changes in the overall vegetation zoning. A model of the changes in the vegetation zones in the Czech Republic was developed at three Czech universities in cooperation with the Czech Hydrometeorological Institute. This paper presents an application of this model to predict the effects of climate change on future climate conditions for sugar beet cultivation in the Czech Republic.