scholarly journals Relationships between columnar aerosol optical properties and surface particulate matter observations in north-central Spain from long-term records (2003–2011)

2014 ◽  
Vol 7 (6) ◽  
pp. 5829-5882 ◽  
Author(s):  
Y. S. Bennouna ◽  
V. Cachorro ◽  
M. A. Burgos ◽  
C. Toledano ◽  
B. Torres ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Annual Cycle ◽  
Central Area ◽  
Central Spain ◽  
North Central ◽  
Desert Dust ◽  
The North ◽  
Daily Data ◽  
Dust Events

Abstract. This work examines the relationships between Aerosol Optical Depth (AOD) and Particulate Matter (PMX) parameters, based on long records (2003–2011) of two nearby sites from the AERONET and EMEP networks in the north-central area of Spain. The climatological annual cycle of PM10 and PM2.5 present a bimodality which might be partly due to desert dust intrusions, a pattern which does not appear in the annual cycle of the AOD. In the case of the AOD, this bimodality is likely to be masked because of the poor sampling of sunphotometer data as compared to PMX (67% of days against 90%), and this fact stresses the necessity of long-term observations. In monthly series, significant interannual variations are observed and most extrema coincide, however the bimodal shape remains relatively stable for PMX. Significant and consistent trends were found for both datasets likely associated to a decrease of desert dust apportionment until 2009. PM10 and AOD daily data are moderately correlated (0.56), a correlation improving for monthly means (0.70). In the case of strong desert dust events day-to-day correlation is not systematic, therefore an extensive analysis on PMX, fine-PM ratio, AOD and associated Ångström exponent (α) is carried out.

The Sydney Cyprus Survey Project: An Interdisciplinary Investigation of Long-Term Change in the North Central Troodos, Cyprus

1999 ◽  
Vol 26 (1) ◽  
pp. 19 ◽  
Author(s):  
Michael Given ◽  
A. Bernard Knapp ◽  
Nathan Meyer ◽  
Timothy E. Gregory ◽  
Vasiliki Kassianidou ◽  
...  
Keyword(s):  
North Central ◽  
The North ◽  
Term Change

Climatology and Trends of Climate Extremes of Temperature and Precipitation in Belo Monte Hydropower Plant – Eastern Amazon, Brazil

2021 ◽  
Author(s):  
Wanderson Luiz-Silva ◽  
Pedro Regoto ◽  
Camila Ferreira de Vasconcellos ◽  
Felipe Bevilaqua Foldes Guimarães ◽  
Katia Cristina Garcia
Keyword(s):  
Climate Change ◽  
Climate Extremes ◽  
Annual Rainfall ◽  
The South ◽  
North Central ◽  
Adaptation Capacity ◽  
The North ◽  
South Central ◽  
Daily Data ◽  
Belo Monte

<p>This research aims to support studies related to the adaptation capacity of the Amazon region to climate change. The Belo Monte Hydroelectric Power Plant (HPP) is in the Xingu River basin, in eastern Amazonia. Deforestation coupled with changes in water bodies that occurred in the drainage area of Belo Monte HPP over the past few decades can significantly influence the hydroclimatic features and, consequently, ecosystems and energy generation in the region. In this context, we analyze the climatology and trends of climate extremes in this area. The climate information comes from daily data in grid points of 0.25° x 0.25° for the period 1980-2013, available in http://careyking.com/data-downloads/. A set of 17 climate extremes indices based on daily data of maximum temperature (TX), minimum temperature (TN), and precipitation (PRCP) was calculated through the RClimDex software, recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). The Mann-Kendall and the Sen’s Curvature tests are used to assess the statistical significance and the magnitude of the trends, respectively. The drainage area of the Belo Monte HPP is dominated by two climatic types: an equatorial climate in the north-central portion of the basin, with high temperatures and little variation throughout the year (22°C to 32°C), in addition to more frequent precipitation; and a tropical climate in the south-central sector, which experiences slightly more pronounced temperature variations throughout the year (20°C to 33°C) and presents a more defined wet and dry periods. The south-central portion of the basin exhibits the highest temperature extremes, with the highest TX and the lowest TN of the year occurring in this area, both due to the predominant days of clear skies in the austral winter, as to the advance of intense masses of polar air at this period. The diurnal temperature range is lower in the north-central sector when compared to that in the south-central region since the first has greater cloud cover and a higher frequency of precipitation. The largest annual rainfall volumes are concentrated at the north and west sides (more than 1,800 mm) and the precipitation extremes are heterogeneous across the basin. The maximum number of consecutive dry days increases from the north (10 to 20 days) to the south (90 to 100 days). The annual frequency of warm days and nights is increasing significantly in a large part of the basin with a magnitude ranging predominantly from +7 to +19 days/decade. The annual rainfall shows a predominant elevation sign of up to +200 mm/decade only in the northern part of the basin, while the remainder shows a reduction of up to -100 mm/decade. The duration of drought periods increases in the south-central sector of the basin, reaching up to +13 days/decade in some areas. The results of this study will be used in the future as an important input, together with exposure, sensibility, and local adaptation capacity, to design adaptation strategies that are more consistent with local reality and to the needs of local communities.</p>

Agricultural Drought in North-Central Mexico

2005 ◽  
Author(s):  
José Alfredo Rodríguez-Pineda ◽  
Lorrain Giddings
Keyword(s):  
Agricultural Land ◽  
Agricultural Drought ◽  
Natural Phenomenon ◽  
North Central ◽  
Water Policies ◽  
The North ◽  
Time Period ◽  
Northern Half ◽  
The Government

Drought is the most significant natural phenomenon that affects the agriculture of northern Mexico. The more drought-prone areas in Mexico fall in the northern half of the country, in the states of Chihuahua, Coahuila, Durango, Zacatecas, and Aguascalientes (figure 10.1). The north-central states form part of the Altiplanicie Mexicana and account for 30.7% of the national territory of 1,959,248 km2. This area is characterized by dry and semidry climates (Garcia, 1981) and recurrent drought periods. The climate of Mexico varies from very dry to subhumid. Very dry climate covers 21%, dry climate covers 28%, and temperate subhumid and hot subhumid climates prevail in 21% and 23% of the national territory, respectively. About 20 years ago, almost 75% of Mexico’s agricultural land was rainfed, and only 25% irrigated (Toledo et al., 1985), making the ratio of rainfed to irrigated area equal to 3. However, for the northern states this ratio was 3.5 during the 1990–98 period (table 10.1). Because of higher percentage of rain-fed agriculture, drought is a common phenomenon in this region, which has turned thousands of hectares of land into desert. Though the government has built dams, reservoirs, and other irrigation systems to alleviate drought effects, rain-fed agriculture (or dryland farming) remains the major form of cultivation in Mexico. In Mexico, there is no standard definition for agricultural drought. However, the Comisión Nacional del Agua (CNA; i.e., National Water Commission), which is a federal agency responsible for making water policies, has coined its own definition for drought. This agency determines whether a particular region has been affected by drought, by studying rainfall records collected from the national climatic network. The national climatic network is spread throughout the country and is managed by the Servicio Meteorológico Nacional (SMN; i.e., National Meteorological Services). The CNA determines, for a municipal region, if the rainfall is equal to or less than one standard deviation from the long-term mean over a time period of two or more consecutive months. If it is, then the secretary of state declares drought for the region.

scholarly journals Long-term variability of dust events in Iceland (1949–2011)

2014 ◽  
Vol 14 (24) ◽  
pp. 13411-13422 ◽  
Author(s):  
P. Dagsson-Waldhauserova ◽  
O. Arnalds ◽  
H. Olafsson
Keyword(s):  
Particulate Matter ◽  
Volcanic Eruptions ◽  
Dust Storms ◽  
The Arctic ◽  
Atmospheric Dust ◽  
The World ◽  
Icelandic Low ◽  
Dust Events ◽  
The 1960S

Abstract. The long-term frequency of atmospheric dust observations was investigated for the southern part of Iceland and interpreted together with earlier results obtained from northeastern (NE) Iceland (Dagsson-Waldhauserova et al., 2013). In total, over 34 dust days per year on average occurred in Iceland based on conventionally used synoptic codes for dust observations. However, frequent volcanic eruptions, with the re-suspension of volcanic materials and dust haze, increased the number of dust events fourfold (135 dust days annually). The position of the Icelandic Low determined whether dust events occurred in the NE (16.4 dust days annually) or in the southern (S) part of Iceland (about 18 dust days annually). The decade with the most frequent dust days in S Iceland was the 1960s, but the 2000s in NE Iceland. A total of 32 severe dust storms (visibility < 500 m) were observed in Iceland with the highest frequency of events during the 2000s in S Iceland. The Arctic dust events (NE Iceland) were typically warm, occurring during summer/autumn (May–September) and during mild southwesterly winds, while the subarctic dust events (S Iceland) were mainly cold, occurring during winter/spring (March–May) and during strong northeasterly winds. About half of the dust events in S Iceland occurred in winter or at sub-zero temperatures. A good correlation was found between particulate matter (PM10) concentrations and visibility during dust observations at the stations Vík and Stórhöfði. This study shows that Iceland is among the dustiest areas of the world and that dust is emitted year-round.

scholarly journals Structural polymorphism in Drosophila subobscura Coll. from various localities in Scotland

1961 ◽  
Vol 2 (1) ◽  
pp. 1-9 ◽  
Author(s):  
G. R. Knight
Keyword(s):  
Western Europe ◽  
Central Area ◽  
Small Chromosome ◽  
Drosophila Subobscura ◽  
Structural Polymorphism ◽  
North Central ◽  
The North ◽  
Break Points ◽  
Two Populations ◽  
Local Race

1. Gunson's salivary chromosome preparations of Drosophila subobscura from widely separated sites in Scotland have been re-examined and inversions recorded according to the Mainx nomenclature.2. Sixty-four diploid sets only were available. Of these, thirty-seven sets were found to be structurally homozygous on all chromosomes.3. From Drumnadrochit in the north-central area of Scotland, the inversion found on the E-chromosome, so far as is known, has not previously been described. Its break-points have been noted, and the inversion is named E14.4. A strain of D. subobscura from the small western island of Iona was the only one found to be completely homozygous in the five long arms of the chromosome set.5. Samples of D. subobscura from two closely related localities in Midlothian, Scotland, also have been examined. Results are based on the analysis of 120 haploid sets in hybrids between the local race and the standard Küsnacht stock.6. A slight difference in type and frequency of inversions has been noted between the two populations. The inversion E1+2 was recorded from Dalkeith, but was absent at Heriot, while U1, present at Heriot, was replaced by UST at Dalkeith.7. The A-chromosome was structurally homozygous throughout.8. Scottish samples of D. subobscura are characterized by their qualitative simplicity of polymorphism, the variety of inversion types being small. Chromosome orders analysed have been compared with those occurring in Western Europe and Israel.

scholarly journals Inventory of African desert dust events in the north-central Iberian Peninsula in 2003–2014 based on sun-photometer–AERONET and particulate-mass–EMEP data

2016 ◽  
Vol 16 (13) ◽  
pp. 8227-8248 ◽  
Author(s):  
Victoria E. Cachorro ◽  
Maria A. Burgos ◽  
David Mateos ◽  
Carlos Toledano ◽  
Yasmine Bennouna ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Human Observer ◽  
North Central ◽  
Desert Dust ◽  
The North ◽  
Western Mediterranean Basin ◽  
Synoptic Conditions ◽  
Particulate Mass ◽  
Sun Photometer ◽  
The Impact

Abstract. A reliable identification of desert dust (DD) episodes over north-central Spain is carried out based on the AErosol RObotic NETwork (AERONET) columnar aerosol sun photometer (aerosol optical depth, AOD, and Ångström exponent, α) and European Monitoring and Evaluation Programme (EMEP) surface particulate-mass concentration (PMx, x = 10, 2.5, and 2.5–10 µm) as the main core data. The impact of DD on background aerosol conditions is detectable by means of aerosol load thresholds and complementary information provided by HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) air mass back trajectories, MODIS (Moderate Resolution Imaging Spectroradiometer) images, forecast aerosol models, and synoptic maps, which have been carefully reviewed by a human observer for each day included in the DD inventory. This identification method allows the detection of low and moderate DD intrusions and also of mixtures of mineral dust with other aerosol types by means of the analysis of α. During the period studied (2003–2014), a total of 152 DD episodes composed of 418 days are identified. Overall, this means ∼ 13 episodes and ∼ 35 days per year with DD intrusion, representing 9.5 % days year−1. During the identified DD intrusions, 19 daily exceedances over 50 µg m−3 are reported at the surface. The occurrence of DD event days during the year peaks in March and June, with a marked minimum in April and lowest occurrence in winter. A large interannual variability is observed showing a statistically significant temporal decreasing trend of ∼ 3 days year−1. The DD impact on the aerosol climatology is addressed by evaluating the DD contribution in magnitude and percent (in brackets) for AOD, PM10, PM2.5, and PM2.5 − 10, obtaining mean values of 0.015 (11.5 %), 1.3 µg m−3 (11.8 %), 0.55 µg m−3 (8.5 %) and 0.79 µg m−3 (16.1 %), respectively. Annual cycles of the DD contribution for AOD and PM10 present two maxima – one in summer (0.03 and 2.4 µg m−3 for AOD in June and PM10 in August) and another in March (0.02 for AOD and 2.2 µg m−3 for PM10) – both displaying a similar evolution with exceptions in July and September. The seasonal cycle of the DD contribution to AOD does not follow the pattern of the total AOD (close to a bell shape), whereas both PM10 cycles (total and DD contribution) are more similar to each other in shape, with an exception in September. The interannual evolution of the DD contribution to AOD and PM10 has evidenced a progressive decrease. This decline in the levels of mineral dust aerosols can explain up to 30 % of the total aerosol load decrease observed in the study area during the period 2003–2014. The relationship between columnar and surface DD contribution shows a correlation coefficient of 0.81 for the interannual averages. Finally, synoptic conditions during DD events are also analysed, observing that the north African thermal low causes most of the events ( ∼  53 %). The results presented in this study highlight the relevance of the area studied since it can be considered representative of the clean background in the western Mediterranean Basin where DD events have a high impact on aerosol load levels.

scholarly journals A twenty-year study on natural and manmade global interannual fluctuations of cirrus cloud cover

2007 ◽  
Vol 7 (1) ◽  
pp. 93-126 ◽  
Author(s):  
K. Eleftheratos ◽  
C. S. Zerefos ◽  
P. Zanis ◽  
D. S. Balis ◽  
G. Tselioudis ◽  
...  
Keyword(s):  
Relative Humidity ◽  
North Atlantic ◽  
Annual Cycle ◽  
Cloud Cover ◽  
Cirrus Cloud ◽  
The North ◽  
Long Term Trends ◽  
The North Atlantic ◽  
The Tropics

Abstract. The seasonal variability and the interannual variance explained by ENSO and NAO to cirrus cloud cover (CCC) are examined during the twenty-year period 1984–2004. CCC was found to be significantly correlated with vertical velocities and relative humidity from ECMWF/ERA40 in the tropics (correlations up to –0.7 and +0.7 at some locations, respectively) suggesting that variations in large-scale vertical winds and relative humidity fields can be the origin of up to half of the local variability in CCC over these regions. These correlations reflect mostly the seasonal cycle. Although the annual cycle is dominant in all latitudes and longitudes, peaking over the tropics and subtropics, its amplitude can be exceeded during strong El Nino/La Nina events. Over the eastern tropical Pacific Ocean the interannual variance of CCC which can be explained by ENSO is about 6.8% and it is ~2.3 times larger than the amplitude of the annual cycle. Natural long-term trends in the tropics are generally small (about –0.3% cloud cover per decade) and possible manmade trends in those regions are also small. The contributions of NAO and QBO to the variance of CCC in the tropics are also small. In the northern mid–latitudes, on the other hand, the effect of NAO is more significant and can be very important regionally. Over northern Europe and the eastern part of the North Atlantic Flight Corridor (NAFC) there is a small positive correlation between CCC and NAO index during the wintertime of about 0.3. In this region, the interannual variance of CCC explained by NAO is 2.6% and the amplitude of the annual cycle is 3.1%. Long-term trends over this region are about +1.6% cloud cover per decade and compare well with the observed manmade trends over congested air traffic regions in Europe and the North Atlantic as have been evidenced from earlier findings.

scholarly journals Biology and Economics of Recommendations for Insecticide-Based Management of Soybean Aphid

2016 ◽  
Vol 17 (4) ◽  
pp. 265-269 ◽  
Author(s):  
Robert L. Koch ◽  
Bruce D. Potter ◽  
Phillip A. Glogoza ◽  
Erin W. Hodgson ◽  
Christian H. Krupke ◽  
...  
Keyword(s):  
Insect Pest ◽  
Soybean Aphid ◽  
North Central ◽  
The North ◽  
Central United States ◽  
Glycine Max L ◽  
Short And Long Term ◽  
Aphis Glycines Matsumura

Soybean aphid, Aphis glycines Matsumura, remains the key insect pest of soybean, Glycine max (L.) Merrill, in the north-central United States. Management of this pest has relied primarily on scouting and application of foliar insecticides based on an economic threshold (ET) of 250 aphids per plant. This review explains why this ET remains valid for soybean aphid management, despite changes in crop value and input costs. In particular, we review how soybean aphid impacts soybean yield, the role of biology and economics in recommendations for soybean aphid management, and the short- and long-term consequences of inappropriately timed insecticide applications. Accepted for publication 13 December 2016.

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