scholarly journals Emergent Rarity Properties in Carabid Communities From Chinese Steppes With Different Climatic Conditions

2021 ◽  
Vol 9 ◽  
Author(s):  
Noelline Tsafack ◽  
Paulo A. V. Borges ◽  
Yingzhong Xie ◽  
Xinpu Wang ◽  
Simone Fattorini
Keyword(s):  
Community Structure ◽  
Environmental Conditions ◽  
Large Scale ◽  
Species Abundance ◽  
Climatic Conditions ◽  
Carabid Beetles ◽  
Model Parameters ◽  
Desert Steppe ◽  
Best Fit ◽  
Scale Of Analysis

Species abundance distributions (SADs) are increasingly used to investigate how species community structure changes in response to environmental variations. SAD models depict the relative abundance of species recorded in a community and express fundamental aspects of the community structure, namely patterns of commonness and rarity. However, the influence of differences in environmental conditions on SAD characteristics is still poorly understood. In this study we used SAD models of carabid beetles (Coleoptera: Carabidae) in three grassland ecosystems (desert, typical, and meadow steppes) in China. These ecosystems are characterized by different aridity conditions, thus offering an opportunity to investigate how SADs are influenced by differences in environmental conditions (mainly aridity and vegetation cover, and hence productivity). We used various SAD models, including the meta-community zero sum multinomial (mZSM), the lognormal (PLN) and Fisher’s logseries (LS), and uni- and multimodal gambin models. Analyses were done at the level of steppe type (coarse scale) and for different sectors within the same steppe (fine scale). We found that the mZSM model provided, in general, the best fit at both analysis scales. Model parameters were influenced by the scale of analysis. Moreover, the LS was the best fit in desert steppe SAD. If abundances are rarefied to the smallest sample, results are similar to those without rarefaction, but differences in models estimates become more evident. Gambin unimodal provided the best fit with the lowest α-value observed in desert steppe and higher values in typical and meadow steppes, with results which were strongly affected by the scale of analysis and the use of rarefaction. Our results indicate that all investigated communities are adequately modeled by two similar distributions, the mZSM and the LS, at both scales of analyses. This indicates (1) that all communities are characterized by a relatively small number of species, most of which are rare, and (2) that the meta-communities at the large scale maintain the basic SAD shape of the local communities. The gambin multimodal models produced exaggerated α-values, which indicates that they overfit simple communities. Overall, Fisher’s α, mZSM θ, and gambin α-values were substantially lower in the desert steppe and higher in the typical and meadow steppes, which implies a decreasing influence of environmental harshness (aridity) from the desert steppe to the typical and meadow steppes.

scholarly journals Identification of a general light use efficiency model for gross primary production

2010 ◽  
Vol 7 (5) ◽  
pp. 7673-7726 ◽  
Author(s):  
J. E. Horn ◽  
K. Schulz
Keyword(s):  
Large Scale ◽  
Gross Primary Production ◽  
Daily Basis ◽  
Climatic Conditions ◽  
Model Parameters ◽  
Light Use Efficiency ◽  
Meteorological Forcing ◽  
Use Efficiency ◽  
Study Sites ◽  
Light Use Efficiency Model

Abstract. Non-stationary and non-linear dynamic time series analysis tools are applied to multi-annual eddy covariance and micrometeorological data from 45 FLUXNET sites to derive a light use efficiency model on a daily basis. The extracted typical behaviour of the canopies in response to meteorological forcing leads to a model formulation allowing a variable influence of the model parameters modulating the light use efficiency. Thereby, the model is applicable to a broad range of vegetation types and climatic conditions. The proposed model explains large proportions of the variation of the gross carbon uptake at the study sites while the optimized set of six parameters is well defined. With the parameters showing explainable and meaningful relations to site-specific environmental conditions, the model has the potential to serve as basis for general regionalization strategies for large scale carbon flux predictions.

scholarly journals Large-scale metabarcoding analysis of epipelagic and mesopelagic copepods in the Pacific

2020 ◽  
Author(s):  
Junya Hirai ◽  
Aiko Tachibana ◽  
Atsushi Tsuda
Keyword(s):  
Community Structure ◽  
Environmental Conditions ◽  
Evolutionary History ◽  
Large Scale ◽  
The Arctic ◽  
Copepod Community ◽  
The Pacific ◽  
Low Latitudes ◽  
The Pacific Ocean ◽  
Epipelagic Layer

AbstractA clear insight into large-scale community structure of planktonic copepods is critical to understanding mechanisms controlling diversity and biogeography of marine taxa, owing to their high abundance, ubiquity, and sensitivity to environmental changes. Here, we applied a 28S metabarcoding approach to large-scale communities of epipelagic and mesopelagic copepods at 70 stations across the Pacific Ocean and three stations in the Arctic Ocean. Major patterns of community structure and diversity, influenced by water mass structures, agreed with results from previous morphology-based studies. However, large-scale metabarcoding approach could detected community changes even under stable environmental conditions, including changes in the north/south subtropical gyres and east/west areas within each subtropical gyre. There were strong effects of epipelagic environment on mesopelagic communities, and community subdivisions were observed in the environmentally-stable mesopelagic layer. In each sampling station, higher operational taxonomic unit (OTU) numbers and lower phylogenetic diversity were observed in the mesopelagic layer than in the epipelagic layer, indicating a recent rapid increase of species numbers in the mesopelagic layer. The phylogenetic analysis utilizing representative sequences of OTUs revealed trends of recent emergence of cold-water OTUs mainly distributed at high latitudes with low water temperatures. Conversely, high diversity of copepods at low latitudes was suggested to have been formed through long evolutionary history under high water temperature. The metabarcoding results suggest that evolutionary processes have strong impacts on current patterns of copepod diversity, and support the “out of the tropics” theory explaining latitudinal diversity gradients of copepods. Both diversity patterns in epipelagic and mesopelagic showed high correlations to sea surface temperature; thus, predicted global warming may have a significant impact on copepod diversity in both layers.Author SummaryMarine planktonic copepods are highly dominant and diverse, and revealing their community structure and diversity is important to understanding marine ecosystems. We used molecular-based metabarcoding to reveal a total of 205 copepod communities in the ‘sunlight’ or epipelagic layer (0– 200 m) and the ‘twilight’ or mesopelagic layer (200–500 m and 500–1,000 m), mainly in the Pacific Ocean (data for 70 stations), but also in the Arctic Ocean (data for three stations). Different copepod communities were found in each geographical region with different environmental conditions, including tropical, subtropical, transition, Kuroshio Current, California Current, subarctic and arctic areas. The metabarcoding method sensitively detected small changes of copepod community even in environmentally-stable subtropical ocean systems and the mesopelagic layer. A high diversity of copepods was detected at low latitudes, and copepod diversity was higher in the mesopelagic layer than in the epipelagic layer in each area. These diversity patterns were influenced by both evolutionary history and present environmental conditions. The copepod community in the mesopelagic layer was strongly influenced by environmental conditions in the epipelagic layer. Thus, predicted climate changes may affect marine ecosystems not only in the epipelagic layer but also in the mesopelagic layer.

scholarly journals Effect of daily variation on the seasonality of testate amoebae community structure in different environments of a Neotropical floodplain

2015 ◽  
Author(s):  
Leilane T. Fatoreto Schwind ◽  
Rodrigo L. Arrieira ◽  
Juliana Déo Dias ◽  
Nadson Ressyé Simões ◽  
Claudia Costa Bonecker ◽  
...  
Keyword(s):  
Community Structure ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Time Lag ◽  
Species Abundance ◽  
Testate Amoebae ◽  
Mantel Test ◽  
Hydrodynamic Characteristics ◽  
Testate Amoeba ◽  
Ecological Communities

<p>Ecological communities are constantly restructuring in the short and long term in response to population dynamics and environmental variables. This study evaluated the structure of arcellinid and euglyphid testate amoebae planktonic communities in three environments of the Upper Paraná River basin, Brazil. We hypothesised that the community structure of testate amoebae is differentially influenced by environmental conditions, mainly in isolated lentic ecosystems, due the effect of the low-water period. In addition, we predicted that the response of testate amoeba communities to environmental changes is also affected by the distinct hydrodynamic characteristics of the environment. Plankton were sampled in the low- and high-water periods, and physical and chemical variables were calculated for each site. In order to evaluate the influence of environmental conditions on the variation in testate amoebae community structure over time, a time-lag analytical approach was used and significance was estimated using a Mantel test. A Kendall test coefficient was used to estimate the maintenance of species abundance on each day when sampling was carried out and for each water body. A redundancy analysis was also performed to assess the responses of testate amoeba communities to environmental change in the three studied environments. Bray–Curtis dissimilarity indices were calculated for the testate amoeba communities and the significance of the differences between communities was estimated using a Mantel test. Seventy-five taxa belonging to six families were identified. Environmental conditions influenced the richness, abundance, and dominance pattern of the testate amoebae communities, and distinct hydrodynamic characteristics of the environments affected the establishment of community structure.</p>

scholarly journals Latitudinal Distribution of Ammonia-Oxidizing Bacteria and Archaea in the Agricultural Soils of Eastern China

2014 ◽  
Vol 80 (18) ◽  
pp. 5593-5602 ◽  
Author(s):  
Hongchen Jiang ◽  
Liuqin Huang ◽  
Ye Deng ◽  
Shang Wang ◽  
Yu Zhou ◽  
...  
Keyword(s):  
Community Structure ◽  
Soil Nutrients ◽  
Environmental Conditions ◽  
Latitudinal Gradient ◽  
Agricultural Soils ◽  
Eastern China ◽  
Climatic Conditions ◽  
Mean Annual Temperature ◽  
Ammonia Oxidizing Bacteria ◽  
Content Type

ABSTRACTThe response of soil ammonia-oxidizing bacterial (AOB) and archaeal (AOA) communities to individual environmental variables (e.g., pH, temperature, and carbon- and nitrogen-related soil nutrients) has been extensively studied, but how these environmental conditions collectively shape AOB and AOA distributions in unmanaged agricultural soils across a large latitudinal gradient remains poorly known. In this study, the AOB and AOA community structure and diversity in 26 agricultural soils collected from eastern China were investigated by using quantitative PCR and bar-coded 454 pyrosequencing of theamoAgene that encodes the alpha subunit of ammonia monooxygenase. The sampling locations span over a 17° latitude gradient and cover a range of climatic conditions. TheNitrosospiraandNitrososphaerawere the dominant clusters of AOB and AOA, respectively; but the subcluster-level composition ofNitrosospira-related AOB andNitrososphaera-related AOA varied across the latitudinal gradient. Variance partitioning analysis showed that geography and climatic conditions (e.g., mean annual temperature and precipitation), as well as carbon-/nitrogen-related soil nutrients, contributed more to the AOB and AOA community variations (∼50% in total) than soil pH (∼10% in total). These results are important in furthering our understanding of environmental conditions influencing AOB and AOA community structure across a range of environmental gradients.

scholarly journals WOODLAND POND SALAMANDER ABUNDANCE IN RELATION TO FOREST MANAGEMENT AND ENVIRONMENTAL CONDITIONS IN NORTHERN WISCONSIN

2015 ◽  
pp. 34-42
Author(s):  
Deahn M. Donner ◽  
Christine A. Ribic ◽  
Albert J. Beck ◽  
Dale Higgins ◽  
Dan Eklund ◽  
...  
Keyword(s):  
Forest Management ◽  
Environmental Conditions ◽  
Large Scale ◽  
Species Abundance ◽  
Canopy Openness ◽  
Climate Conditions ◽  
Monitoring Programs ◽  
Ambystoma Laterale ◽  
Surrounding Landscape ◽  
Woodland Ponds

Woodland ponds are important landscape features that help sustain populations of amphibians that require this aquatic habitat for successful reproduction. Species abundance patterns often reflect site-specific differences in hydrology, physical characteristics, and surrounding vegetation. Large-scale processes such as changing land cover and environmental conditions are other potential drivers influencing amphibian populations in the Upper Midwest, but little information exists on the combined effects of these factors. We used Blue-spotted (Ambystoma laterale Hallowell) and Spotted Salamander (A. maculatum Shaw) monitoring data collected at the same woodland ponds thirteen years apart to determine if changing environmental conditions and vegetation cover in surrounding landscapes influenced salamander movement phenology and abundance. Four woodland ponds in northern Wisconsin were sampled for salamanders in April 1992-1994 and 2005-2007. While Bluespotted Salamanders were more abundant than Spotted Salamanders in all ponds, there was no change in the numbers of either species over the years. However, peak numbers of Blue-spotted Salamanders occurred 11.7 days earlier (range: 9-14 days) in the 2000s compared to the 1990s; Spotted Salamanders occurred 9.5 days earlier (range: 3 - 13 days). Air and water temperatures (April 13- 24) increased, on average, 4.8 oC and 3.7 oC, respectively, between the decades regardless of pond. There were no discernible changes in canopy openness in surrounding forests between decades that would have warmed the water sooner (i.e., more light penetration). Our finding that salamander breeding phenology can vary by roughly 10 days in Wisconsin contributes to growing evidence that amphibian populations have responded to changing climate conditions by shifting life-cycle events. Managers can use this information to adjust monitoring programs and forest management activities in the surrounding landscape to avoid vulnerable amphibian movement periods. Considering direct and indirect stressors such as changing habitat and environmental conditions simultaneously to better understand trends in space and time can help improve monitoring programs for this taxa, which is at major risk of continued declines.

scholarly journals Komposisi dan Kelimpahan Ophiuroidea dan Echinoidea di Perairan Pantai Pok Tunggal, Gunung Kidul, Yogyakarta

2020 ◽  
Vol 9 (2) ◽  
pp. 109-118
Author(s):  
Herlina Lestari Pakpahan ◽  
Irwani Irwani ◽  
Ita Widowati
Keyword(s):  
Water Quality ◽  
Community Structure ◽  
Data Analysis ◽  
Coral Reefs ◽  
Environmental Conditions ◽  
Diversity Index ◽  
Species Abundance ◽  
Temperature Data ◽  
Dominance Index ◽  
Index Value

ABSTRAK: Echinodermata merupakan salah satu komponen penting dalam keaneka ragaman fauna di ekosistem pantai. Habitat utama echinodermata adalah terumbu karang, hal ini karena terumbu karang berperan sebagai tempat berlindung dan mencari makan bagi fauna echinodermata. Salah satu penyebaran biota ini adalah di perairan rataan terumbu karang pantai selatan di pantai Pok Tunggal, Gunung Kidul, Yogyakarta. Tujuan penelitian ini adalah untuk mengetahui jenis dan struktur komunitas echinodermata di pantai Pok Tunggal,  kabupaten Gunung Kidul, Yogyakarta. Penelitian ini dilaksanakan pada bulan Juli 2019 di pantai Pok Tunggal. Metode pengambilan data kelimpahan menggunakan metode transek kuadrat berukuran 1x1 m, parameter kualitas perairan yang diukur adalah salinitas, DO, pH, serta suhu. Analisis  data meliputi identifikasi spesies, kelimpahan jenis (ind/m2), indeks keanekaragaman, indeks keseragaman dan indeks dominansi. Hasil pengamatan ditemukan beberapa spesies, dari 2 kelas filum echinodermata, antara lain 2 species dari kelas Ophiuroidea yaitu Ophiocoma erinaceus dan Ophiocoma dentata, 3 species dari kelas Echinoidea yaitu Echinometra oblonga, Echinometra mathei dan Echinothrix diadema. Hasil penelitian menunjukkan kelimpahan individu tertinggi adalah Echinometra oblonga (16,6 ind/m2) dan terendah adalah Echinothrix diadema (0,4 ind/m2). Parameter lingkungan perairan di pantai Pok Tunggal pada setiap stasiun masih menunjang kehidupan Echinodermata. Struktur komunitas echinodermata yaitu nilai indeks keanekaragaman (H‟) berkisar antara 0,667-1,198, nilai indeks keseragaman (E) berkisar antara 0,744 - 0,999 dan nilai indeks dominansi (C) berkisar berkisar 0,308 - 0,525. ABSTRACT: Echinoderms are one of important component of fauna diversity in coastal ecosystems. The main habitat of Echinoderms is coral reefs, because coral reefs act as a shelter and food for echinoderms fauna. This species distributed in the flat waters of the coral reefs of the south coast at Pok Tunggal beach, Gunung Kidul, Yogyakarta. The aim of this study was to determine the species and Community Structure of echinoderms on the Pok Tunggal beach, Gunung Kidul Regency, Yogyakarta. This research was conducted in July 2018 at Pok Tunggal Beach. Sampling was done by using transect quadrant measuring 1x1 m. Parameter of water quality was salinity, DO, pH, and temperature. Data analysis includes species abundance (ind/m2), diversity index, uniformity index and dominance index. The result showed that several species of Echinodermal phylum classes, including 2 species of Ophiuroidea class namely Ophiocoma erinaceus and Ophiocoma dentata, 3 species of Echinoidea class namely Echinometra oblonga, Echinometra mathei and Echinothrix diadema. The highest individual abundance was Echinometra oblonga (16,6 ind/m2) and the lowest was Echinothrix diadema (0,4 ind/m2). The environmental conditions of the waters at the Pok Tunggal beach at each station can support the life of echinoderms. Echinoderms community structure, namely diversity index (H ') ranges from 0,667-1,198, uniformity index (E) ranges from 0,744-0,999 and dominance index value ranges (C) ranges from 0,308-0,525.

scholarly journals Diversity Patterns of Dung Beetles along a Mediterranean Elevational Gradient

Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 781
Author(s):  
Cristina Mantoni ◽  
Noelline Tsafack ◽  
Ettore Palusci ◽  
Stefano Di Pietro ◽  
Simone Fattorini
Keyword(s):  
Environmental Conditions ◽  
Central Italy ◽  
Species Abundance ◽  
Dung Beetle ◽  
Elevational Gradient ◽  
Complete Characterization ◽  
Climatic Conditions ◽  
Dung Beetles ◽  
Positive Effects ◽  
Taxonomic Groups

Most studies of biodiversity–elevational patterns do not take species abundance into consideration. Hill numbers are a unified family of indices that use species abundance and allow a complete characterization of species assemblages through diversity profiles. Studies on dung beetle responses to elevation were essentially based on species richness and produced inconsistent results because of the non-distinction between different habitats and the use of gradients dispersed over wide areas. We analyzed dung beetle diversity in a Mediterranean mountain (central Italy) for different habitats (woodlands vs. grasslands) and taxonomic groups (scarabaeids and aphodiids). Scarabaeids were the most abundant. Since scarabaeids are able to construct subterranean nests, this indicates that the warm and dry summer climatic conditions of high elevations favor species capable of protecting their larvae from desiccation. Dung beetles were more abundant and diversified in grasslands than in woodlands, which is consistent with their preference for open habitats. In the woodlands, diversity increased with increasing elevation because of increasing tree thinning, whereas, in the grasslands, diversity decreased with elevation because of increasingly harsher environmental conditions. These results indicate a trade-off in the beetle response to elevation between the positive effects of increasing the availability of more suitable habitats and the decrease of optimal environmental conditions.

Dissolved oxygen and temperature best predict deep-sea fish community structure in the Gulf of California with climate change implications

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Community Composition ◽  
Environmental Conditions ◽  
Deep Sea ◽  
Gulf Of California ◽  
Fish Community ◽  
Demersal Fish ◽  
Fish Community Structure ◽  
Explained Variance

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.

scholarly journals A Sensitivity Analysis of the SPACSYS Model

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 624
Author(s):  
Yan Shan ◽  
Mingbin Huang ◽  
Paul Harris ◽  
Lianhai Wu
Keyword(s):  
Sensitivity Analysis ◽  
Wheat Yield ◽  
Climatic Conditions ◽  
Water Dynamics ◽  
Ecological Modelling ◽  
Soil Conditions ◽  
Model Parameters ◽  
Nutrient Inputs ◽  
Nutrient Pool ◽  
Wheat Field

A sensitivity analysis is critical for determining the relative importance of model parameters to their influence on the simulated outputs from a process-based model. In this study, a sensitivity analysis for the SPACSYS model, first published in Ecological Modelling (Wu, et al., 2007), was conducted with respect to changes in 61 input parameters and their influence on 27 output variables. Parameter sensitivity was conducted in a ‘one at a time’ manner and objectively assessed through a single statistical diagnostic (normalized root mean square deviation) which ranked parameters according to their influence of each output variable in turn. A winter wheat field experiment provided the case study data. Two sets of weather elements to represent different climatic conditions and four different soil types were specified, where results indicated little influence on these specifications for the identification of the most sensitive parameters. Soil conditions and management were found to affect the ranking of parameter sensitivities more strongly than weather conditions for the selected outputs. Parameters related to drainage were strongly influential for simulations of soil water dynamics, yield and biomass of wheat, runoff, and leaching from soil during individual and consecutive growing years. Wheat yield and biomass simulations were sensitive to the ‘ammonium immobilised fraction’ parameter that related to soil mineralization and immobilisation. Simulations of CO2 release from the soil and soil nutrient pool changes were most sensitive to external nutrient inputs and the process of denitrification, mineralization, and decomposition. This study provides important evidence of which SPACSYS parameters require the most care in their specification. Moving forward, this evidence can help direct efficient sampling and lab analyses for increased accuracy of such parameters. Results provide a useful reference for model users on which parameters are most influential for different simulation goals, which in turn provides better informed decision making for farmers and government policy alike.

scholarly journals Spatial and Temporal Characteristics of Environmental Air Quality and Its Relationship with Seasonal Climatic Conditions in Eastern China during 2015–2018

2021 ◽  
Vol 18 (9) ◽  
pp. 4524
Author(s):  
Zhiyuan Wang ◽  
Xiaoyi Shi ◽  
Chunhua Pan ◽  
Sisi Wang
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Air Pollutants ◽  
Large Scale ◽  
Asian Summer Monsoon ◽  
Eastern China ◽  
Climatic Conditions ◽  
Uniform Structure ◽  
Concentration Limit ◽  
Environmental Air

Exploring the relationship between environmental air quality (EAQ) and climatic conditions on a large scale can help better understand the main distribution characteristics and the mechanisms of EAQ in China, which is significant for the implementation of policies of joint prevention and control of regional air pollution. In this study, we used the concentrations of six conventional air pollutants, i.e., carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), fine particulate matter (PM2.5), coarse particulate matter (PM10), and ozone (O3), derived from about 1300 monitoring sites in eastern China (EC) from January 2015 to December 2018. Exploiting the grading concentration limit (GB3095-2012) of various pollutants in China, we also calculated the monthly average air quality index (AQI) in EC. The results show that, generally, the EAQ has improved in all seasons in EC from 2015 to 2018. In particular, the concentrations of conventional air pollutants, such as CO, SO2, and NO2, have been decreasing year by year. However, the concentrations of particulate matter, such as PM2.5 and PM10, have changed little, and the O3 concentration increased from 2015 to 2018. Empirical mode decomposition (EOF) was used to analyze the major patterns of AQI in EC. The first mode (EOF1) was characterized by a uniform structure in AQI over EC. These phenomena are due to the precipitation variability associated with the East Asian summer monsoon (EASM), referred to as the “summer–winter” pattern. The second EOF mode (EOF2) showed that the AQI over EC is a north–south dipole pattern, which is bound by the Qinling Mountains and Huaihe River (about 35° N). The EOF2 is mainly caused by seasonal variations of the mixed concentration of PM2.5 and O3. Associated with EOF2, the Mongolia–Siberian High influences the AQI variation over northern EC by dominating the low-level winds (10 m and 850 hPa) in autumn and winter, and precipitation affects the AQI variation over southern EC in spring and summer.

Sign in / Sign up

Export Citation Format

Share Document