Long-term Temporal Variation Research Articles

Analysis of Changes in Water Body Area in Southwest, China Based on GEE

It is of great significance for policymakers to develop management strategies for water resource regulation, habitat protection and wetland restoration. Based on the Google Earth Engine platform, this study extracted remote sensing data of water quality change in Southwest China in the past 20 years, combined with ArcGIS for spatial analysis, and used M-K trend test and mutation test to analyze the long-term temporal variation of water bodies in Southwest China. The analysis shows that the water area in Southwest China increased every five years from 2000 to 2020, but the growth rate changed, while the growth rate slowed down from 2010 to 2020, and the increase mainly occurred in the central and western regions. The results show that in the past 20 years, the water surface area in Southwest China has shown a statistically significant increasing trend, especially after 2020, this trend is more statistically significant. This study can provide a theoretical basis for the protection of water environment in Southwest China.

Immigration and seasonal bottlenecks: high inbreeding despite high genetic diversity in an oscillating population of Culicoides sonorensis (Diptera: Ceratopogonidae).

Most population genetic studies concern spatial genetic differentiation, but far fewer aim at analyzing the temporal genetic changes that occur within populations. Vector species, including mosquitoes and biting midges, are often characterized by oscillating adult population densities, which may affect their dispersal, selection, and genetic diversity over time. Here, we used a population of Culicoides sonorensis from a single site in California to investigate short-term (intra-annual) and long-term (inter-annual) temporal variation in genetic diversity over a 3 yr period. This biting midge species is the primary vector of several viruses affecting both wildlife and livestock, thus a better understanding of the population dynamics of this species can help inform epidemiological studies. We found no significant genetic differentiation between months or years, and no correlation between adult populations and the inbreeding coefficient (FIS). However, we show that repeated periods of low adult abundance during cooler winter months resulted in recurring bottleneck events. Interestingly, we also found a high number of private and rare alleles, which suggests both a large, stable population, as well as a constant influx of migrants from nearby populations. Overall, we showed that the high number of migrants maintains a high level of genetic diversity by introducing new alleles, while this increased diversity is counterbalanced by recurrent bottleneck events potentially purging unfit alleles each year. These results highlight the temporal influences on population structure and genetic diversity in C. sonorensis and provide insight into factors effecting genetic variation that may occur in other vector species with fluctuating populations.

An in situ analyzer for long-term monitoring of nitrite in seawater with versatile liquid waveguide capillary cells: Development, optimization and application

An automatic analyzer coupled with a versatile liquid waveguide capillary cell (LWCC) of different lengths for long-term in situ monitoring of nitrite in seawater was developed based on sequential injection analysis and spectrophotometry. Laboratory experiments have been carried out to analyze the impact of system parameters and environmental factors to obtain the optimal in situ detection performance of the analyzer. By utilizing 10 cm and 50 cm LWCCs, the analyzer can detect nitrite ([NO2−]) concentrations from 0.063 to 6.5 μM and 0.025 to 0.5 μM, and reach detection limits of 0.0189 μM and 0.0076 μM respectively. The short optical path (10 cm) analyzer was tested in situ during a scientific research cruise and then deployed at a coastal experiment station for one month to test the analyzer long-term measurement reliability and monitor nitrite temporal variation. The long optical path (50 cm) analyzer was deployed in a low nutrient coral reef waters over 50 days and the CTD, turbidity, dissolved oxygen and chlorophyll a data were synchronously acquired through a multi-parameter probe, and the distinct relationship between the in situ monitoring results was discussed.

Long-Term Spatial and Temporal Variation of Near Surface Air Temperature in Southwest China During 1969–2018

Near surface air temperature (NSAT) is one of the most important climatic parameters and its variability plays a vital role in natural processes associated with climate. Based on an improved ANUSPLIN (short for Australian National University Spline) model which considers more terrain-related factors, this study analyzed the trends, anomalies, change points, and variations of NSAT in Southwest China from 1969 to 2018. The results revealed that the improved approach performed the best in terms of Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and R-squared (R2) comparing to the conventional ANUSPLIN and co-kriging methods. It has great potential for future meteorological and climatological research, especially in mountainous regions with diverse topography. In addition, Southwest China experienced an overall warming trend of 0.21°C/decade for annual mean NSAT in the period 1969–2018. The warming rate was much higher than mainland China and global averages, and statistically significant warming began in the late 1990s. Moreover, consistent warming and significant elevation-dependent warming (EDW) were observed in most parts of Southwest China, and the hiatus or slowdown phenomenon after the 1997/1998 EL Niño event was not observed as expected. Furthermore, the remarkable increase in winter and minimum NSATs contributed more to the whole warming than summer and maximum NSATs. These findings imply that Southwest China responds to global warming more sensitively than generally recognized, and climate change in mountainous regions like Southwest China should be of particular concern.

Modelling long-term and short-term temporal variation and uncertainty of electricity production in the life cycle assessment of buildings

The building stock is a major contributor to energy consumption and greenhouse gases emissions (GHG), which can be evaluated using life cycle assessment (LCA). Electrification of buildings, e.g. replacing fuel and gas boilers with heat pumps, in order to reduce these emissions is often seen as an option, but this will have short term effects by increasing peak demand, and long term effects by requiring more electricity production capacities. In this paper, a methodology to account for such interaction in LCA is presented. It connects three models addressing: market allocation on a national scale over a long term period, short term variation (i.e. seasonal, daily and hourly) of the electricity mix also on a national scale, and building energy simulation at the scale of one building. This methodology has been applied to a case study including a sample of buildings in the French context, but it can be used in other countries. Six buildings have been studied over 100 years considering 50 energy transition scenarios. Results show that the environmental impacts vary more depending on the scenarios than on the types of the building. Marginal mixes considered in consequential LCA are mainly composed of coal, gas, nuclear and peak technology production which explains the highest values of the different impacts compared to average mixes used in attributional LCA. This approach allows to address uncertainties related to electricity production.

Spatial structure and dispersal dynamics in a house sparrow metapopulation.

The effects of spatial structure on metapopulation dynamics depend upon the interaction between local population dynamics and dispersal, and how this relationship is affected by the geographical isolation and spatial heterogeneity in habitat characteristics. Our aim is to examine how emigration and immigration of house sparrows Passer domesticus in a Norwegian archipelagic metapopulation are affected by key factors predicted by classic metapopulation models to affect dispersal-spatial and temporal variation in population size, inter-island distance, local demography and habitat characteristics. This metapopulation can be divided into two major habitat types: (a) islands closer to the mainland where sparrows breed in colonies on farms, and (b) islands without farms, situated farther away from the mainland where sparrows are exposed to harsher environmental conditions. Dispersal was spatially structured within the metapopulation; there was proportionally and numerically less emigration and immigration involving farm islands, as compared to non-farm islands. Furthermore, emigration and immigration occurred mostly between nearby islands. Moreover, emigration in response to spatial differences in mean population size differed between the habitat types, but populations with large mean received more immigrants in both habitat types. The number of emigrants and immigrants was negatively related to long-term recruit production, which was not the case in non-farm islands. The proportion and number of emigrants was positively related to temporal increases in recruit production on farm islands, however not on non-farm islands. Our results demonstrate that spatial heterogeneity in environmental conditions influences how spatial variation in long-term mean population size, and temporal and spatial variation in recruit production, affects dispersal dynamics. The spatial structure of this metapopulation is therefore best described by a spatially explicit model in which the exchange of individuals within each habitat type is strongly affected by the degree of geographical isolation, population size and recruit production. However, these relationships differed between the two habitat types; non-farm islands showing similarities to a mainland-island model type of structure, whereas farm islands showed features more associated with source-sink or balanced dispersal models. Such differential dispersal dynamics between habitat types are expected to have important consequences for the ecological and evolutionary dynamics within this metapopulation.

The multidecadal spatial pattern of erosion on sandstone shore platforms in south-eastern Australia

Knowledge of the spatial pattern of erosion on shore platforms is needed to better understand their evolution. The long-term spatial and temporal variation of downwearing remains difficult to interpret from erosion data commonly collected over 1–3 years of monitoring. We report erosion data recorded with a micro-erosion meter (MEM) over 40 years (1979–2019) on sandstone shore platforms in a micro-tidal environment along the Otway coast, Victoria, Australia. This well-preserved monitoring network (43 out of 44 original MEM sites) allowed a detailed investigation over a multidecadal timescale not previously considered. Over 40 years the mean erosion rate was 0.25 mm/yr. This value was statistically similar to erosion rates calculated over 2-year (0.32 mm/yr) and 32-year (0.26 mm/yr) periods. In the vertical plane, two significant but opposite relationships between elevation and erosion rates were displayed in the central intertidal zone. There was also a peak in the erosion rate near mean higher high water level. This spatial pattern was strongly associated with wetting and drying controlled by tides and waves. At elevations lower than mean higher low water, downwearing rates were one or two orders of magnitude lower than the average rate of the entire platform. The low erosion rates may be caused by the longer wetting condition of surfaces at lower elevation. Fast erosion rates were recorded in the upper intertidal zone where the bedrock was only inundated by spring high tides or storm waves. Salt weathering may be the primary mechanism but the effect of thermal weathering cannot be neglected at higher elevation. Based on the experience from the near complete MEM network in the study area, suggestions were provided to extend the longevity of monitoring network for future long-term erosion records on shore platforms.

How Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Progresses: The Natural History of ME/CFS.

We propose a framework for understanding and interpreting the pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) that considers wider determinants of health and long-term temporal variation in pathophysiological features and disease phenotype throughout the natural history of the disease. As in other chronic diseases, ME/CFS evolves through different stages, from asymptomatic predisposition, progressing to a prodromal stage, and then to symptomatic disease. Disease incidence depends on genetic makeup and environment factors, the exposure to singular or repeated insults, and the nature of the host response. In people who develop ME/CFS, normal homeostatic processes in response to adverse insults may be replaced by aberrant responses leading to dysfunctional states. Thus, the predominantly neuro-immune manifestations, underlined by a hyper-metabolic state, that characterize early disease, may be followed by various processes leading to multi-systemic abnormalities and related symptoms. This abnormal state and the effects of a range of mediators such as products of oxidative and nitrosamine stress, may lead to progressive cell and metabolic dysfunction culminating in a hypometabolic state with low energy production. These processes do not seem to happen uniformly; although a spiraling of progressive inter-related and self-sustaining abnormalities may ensue, reversion to states of milder abnormalities is possible if the host is able to restate responses to improve homeostatic equilibrium. With time variation in disease presentation, no single ME/CFS case description, set of diagnostic criteria, or molecular feature is currently representative of all patients at different disease stages. While acknowledging its limitations due to the incomplete research evidence, we suggest the proposed framework may support future research design and health care interventions for people with ME/CFS.

Modeling Long-Term Temporal Variation of Dew Formation in Jordan and Its Link to Climate Change

In this study, we performed model simulations to investigate the spatial, seasonal, and annual dew yield during 40 years (1979–2018) at ten locations reflecting the variation of climate and environmental conditions in Jordan. In accordance with the climate zones in Jordan, the dew formation had distinguished characteristics features with respect to the yield, seasonal variation, and spatial variation. The highest water dew yield (an overall annual mean cumulative dew yield as high as 88 mm) was obtained for the Mountains Heights Plateau, which has a Mediterranean climate. The least dew yield (as low as 19 mm) was obtained in Badia, which has an arid climate. The dew yield had a decreasing trend in the past 40 years due to climate change impacts such as increased desertification and the potential of sand and dust storms in the region. In addition, increased anthropogenic air pollution slows down the conversion of vapor to liquid phase change, which also impacts the potential of dew formation. The dew yield showed three distinguished seasonal patterns reflecting the three climates in Jordan. The Mountains Heights Plateau (Mediterranean climate) has the highest potential for dew harvesting (especially during the summer) than Badia (semi-arid climate).

Stabilization for the secondary species contribution to PM2.5 in the Pearl River Delta (PRD) over the past decade, China: A meta-analysis

The fine particulate matter (PM2.5) pollution is one of the atmospheric environmental problems in densely populated areas of China. The secondary species contribution in PM2.5 is extensively studied but the comprehensive analysis on the long-term trend of the secondary species and the main drivers of this trend in the Pearl River Delta (PRD) have not been explored. Therefore, this study aimed to evaluate the long-term temporal variation of PM2.5 and its secondary species contribution in PRD for twenty years from 2000 to 2019. The results of the meta-analysis showed that the annual average concentration of PM2.5 in the PRD was 60.3 ± 16.8 μg/m3 and generally decreased by 3.9 μg/m3 per year from 2004 to 2019. Three significant transitions in secondary species percentage were observed during 2000–2019: first declined in 2000–2005 before rose in 2005–2008 and followed by a stable period in 2008–2019. The percentage of secondary species stabilized at around 80%, of which secondary organic aerosol (SOA) and secondary inorganic aerosol (SIA, including SO42−, NO3−, and NH4+) had identical contributions to PM2.5 over the past decade. SOA was affected by the concentration of total oxidant (OX) and volatile organic compounds (VOCs) emissions. SO42− and SO2 have declined with significant reductions in SO2 emissions. NO3− and NH4+ were positively and negatively correlated with the atmospheric concentration of NO2 and NH3, respectively. In addition to the current efforts on SO2 and NOx controls, further measures are needed to control NH3 and VOCs emissions over a larger area for PRD to effectively improve the air quality.

Research progress on the effects of biochar application on soil fauna community

Soil fauna is an indispensable component of soil biotic communities and an important biological driver controlling soil ecological processes. Exploring the effect of biochar on soil fauna community and their relationship, is of great significance to understand the ecological process and services of soil ecosystem. We reviewed the changes and possible mechanisms of soil fauna community to biochar application. The effect of biochar application on soil fauna was caused directly by the difference of raw material, carbonization temperature, and application amount, and indirectly by the changes of biotic factor, including changes of plant physiological characters and microbe biomass, and changes of abiotic parameters (e.g. soil physiochemical characters). The growth, reproduction and behavior of soil fauna could be promoted under low amount of biochar application (mass ratio <5%). In contrast, toxicity effect occurred with a heavy application (>10%). Meanwhile, activities of soil fauna would affect the stability of biochar, and its ecological and environmental role. A road map for future researches about biochar and soil fauna interaction must focus on long-term field studies, spatial and temporal variation, merge of multi-discipline, and comprehensive analysis and prediction.

A modeling study of the regional representativeness of surface ozone variation at the WMO/GAW background stations in China

Abstract Six World Meteorological Organization (WMO)/Global Atmosphere Watch (GAW) stations are located at background sites in China, which constitute a network for monitoring surface ozone, including its long-term temporal variation. In this study, we evaluated the seasonal variation in surface ozone simulated by the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model with the measurements made at these WMO/GAW background stations for the period of 2010–2012, and investigated the regional representativeness of each station with respect to the seasonal variation in surface ozone. We determined the contributions of ozone originating from various tropospheric and stratospheric latitude bands based on EMAC simulations using a tagged tracer approach. The results showed that the predominant contribution to surface ozone was from the troposphere in northern middle-high and tropical latitudes. For each station there was a large surrounding area in which the yearly ozone maximum occurred in the same month as it did at the station, reflecting the regional characteristics of the seasonal variation in surface ozone recorded at the WMO/GAW background stations. Surface ozone in China was found to generally peak in summer over non-monsoon and mid-latitude monsoon regions and in spring over low-latitude monsoon regions, indicating that the regional representativeness of ozone variability in China is significantly influenced by the Asian summer monsoon.

Long-term temporal variation in the parasite community structure of metazoans of Pimelodus blochii (Pimelodidae), a catfish from the Brazilian Amazon.

The Amazon represents one of the most complex biomes in the world; however, the temporal variations in parasite community structure of fishes inhabiting this region remain poorly understood. Therefore, processes generating such variations are still unknown. The present study evaluated the long-term temporal variation of communitystructure of metazoan parasites of Pimelodus blochii collected in Iaco River, State of Acre (Southwestern Brazilian Amazon). A total of 196 parasites were collected over a 6-year period (2012-2017). Twenty-four different taxa of parasites were found, of which 5 Monogenea, 11 Nematoda, 3 Digenea, 1 Acanthocephala, 1 Cestoda, and 3 Crustacea. The overall species richness ranged from 4 in 2012 to 17 in 2016, in which nematodes (larvae and adults) showed higher numerical dominance, diversity, and species richness. However, the annual species richness was similar between the study years, except in 2016, where it showed a distinctly higher value. The overall parasite diversity was also different in 2012 and 2016, whereas the overall abundance differed in 2013 and 2017. The prevalence and abundance of some infracommunities of parasites varied over time. The temporal changes in the parasite community structure of P. blochii are probably related to variations in host-related features, i.e., body size and shift in diet composition as well as to the occurrence of parasites with distinct life history and biology (mainly monogeneans, digeneans, and nematodes). This is the first evaluation of a long-term temporal variation in the structure of the parasite community in fish from the Amazon.

Satellite-Derived Correlation of SO2, NO2, and Aerosol Optical Depth with Meteorological Conditions over East Asia from 2005 to 2015

Intense economic and industrial development in China has been accompanied by severe local air pollution, as well as in other downwind countries in East Asia. This study analyzes satellite observational data of sulfur dioxide (SO2), nitrogen dioxide (NO2), and aerosol optical depth (AOD) to explore the spatial distribution, long-term temporal variation, and correlation to meteorological conditions over this region over the period 2005–2015. SO2 and NO2 data are retrieved from the ozone monitoring instrument (OMI) onboard the National Aeronautics and Space Administration (NASA) Aura satellite, while AOD data are from the moderate-resolution imaging spectroradiometer (MODIS) onboard the NASA Aqua satellite. Spatial distributions of SO2, NO2, and AOD show the highest levels in the North China Plain (NCP), with hotspots also in Southeastern China (SC) and the Sichuan Basin (SB). Biomass burning also contributes to a high level of AOD in Southeast Asia in spring and in Equatorial Asia in fall. Considering the correlation of pollutant levels to meteorological conditions, monitoring data show that higher temperature and higher relative humidity (RH) favor the conversion of SO2 and NO2 to sulfate and nitrate aerosol, respectively. The impact of stronger lower tropospheric stability facilitates the accumulation of SO2 and NO2 in NCP and SC. Transport of SO2 and NO2 from intense source regions to relatively clean regions is highly influential over East Asia; such transport from the NCP leads to a considerable increase of pollutants in SC, SB, Taiwan Island (TW), and Taiwan Strait (TWS), particularly in winter. Aerosols generated by biomass burning in Southeast Asia and anthropogenic aerosol in SC are transported to TW and TWS and lead to the increase of AOD, with the highest levels of AOD in SC, TW, and TWS occurring in spring. Precipitation results in the removal of pollutants, especially in highly polluted regions, the effect of which is most significant in winter and spring.

Long-term soil metal exposure impaired temporal variation in microbial metatranscriptomes and enriched active phages

BackgroundIt remains unclear whether adaptation and changes in diversity associated to a long-term perturbation are sufficient to ensure functional resilience of soil microbial communities. We used RNA-based approaches (16S rRNA gene transcript amplicon coupled to shotgun mRNA sequencing) to study the legacy effects of a century-long soil copper (Cu) pollution on microbial activity and composition, as well as its effect on the capacity of the microbial community to react to temporal fluctuations.ResultsDespite evidence of microbial adaptation (e.g., iron homeostasis and avoidance/resistance strategies), increased heterogeneity and richness loss in transcribed gene pools were observed with increasing soil Cu, together with an unexpected predominance of phage mRNA signatures. Apparently, phage activation was either triggered directly by Cu, or indirectly via enhanced expression of DNA repair/SOS response systems in Cu-exposed bacteria. Even though total soil carbon and nitrogen had accumulated with increasing Cu, a reduction in temporally induced mRNA functions was observed. Microbial temporal response groups (TRGs, groups of microbes with a specific temporal response) were heavily affected by Cu, both in abundance and phylogenetic composition.ConclusionAltogether, results point toward a Cu-mediated “decoupling” between environmental fluctuations and microbial activity, where Cu-exposed microbes stopped fulfilling their expected contributions to soil functioning relative to the control. Nevertheless, some functions remained active in February despite Cu, concomitant with an increase in phage mRNA signatures, highlighting that somehow, microbial activity is still happening under these adverse conditions.

On Quasi-biennial Oscillations in Chromospheric Macrospicules and Their Potential Relation to the Global Solar Magnetic Field

Abstract This study aims to provide further evidence for the potential influence of the global solar magnetic field on localized chromospheric jets, the macrospicules (MS). To find a connection between the long-term variation of properties of MS and other solar activity proxies, including, e.g., the temporal variation of the frequency shift of solar global oscillations, sunspot area, etc., a database overarching seven years of observations was compiled. This database contains 362 MS, based on observations at the 30.4 nm of the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Three of the five investigated physical properties of MS show a clear long-term temporal variation after smoothing the raw data. Wavelet analysis of the temporal variation of maximum length, maximum area, and average velocity is carried out. The results reveal a strong pattern of periodicities at around 2 years (also referred to as quasi-biennial oscillations—QBOs). A comparison with solar activity proxies that also possess the properties of QBOs provides some interesting features: the minima and maxima of QBOs of MS properties occur at around the same epoch as the minima and maxima of these activity proxies. For most of the time span investigated, the oscillations are out of phase. This out-of-phase behavior was also corroborated by a cross-correlation analysis. These results suggest that the physical processes that generate and drive the long-term evolution of the global solar activity proxies may be coupled to the short-term local physical processes driving the macrospicules, and, therefore modulate the properties of local dynamics.

Correlates of fish and aquatic macrophyte beta diversity in the Upper Paraná River floodplain

We investigated correlates of long-term temporal variation in the beta diversity of macrophytes, sedentary fish, and migratory fish communities in the Upper Parana River floodplain. Two metrics of among-site variation in community composition were calculated in up to 45 sampling periods over 12 years for each biological group. We then tested the following beta diversity correlates: richness and proportion of non-native species, ecosystem productivity proxies, environmental heterogeneity, and hydrological regime proxies. Despite the uncertainty regarding the best model, we found that environmental heterogeneity was the most consistent predictor of beta diversity variation. Non-native species (richness or proportional abundance), productivity, and hydrology were not consistently correlated with beta diversity. However, models results suggest that the likely intensification of threats caused by oligotrophication, non-native species spread, and damming may trigger the effects of these predictors. Thus, we suggest that continuation of the long-term ecological study in the Upper Parana River floodplain is key to our better understanding of the role of these processes in beta diversity variation.

Temporal Variation in the Abundance and Timing of Daily Activity of Chagas Disease Vector Triatoma gerstaeckeri (Stål, 1859) in a Natural Habitat in the Lower Rio Grande Valley, South Texas.

Chagas disease caused by Trypanosoma cruzi is a burden to millions of people in South and Central America. A sylvatic life cycle of the parasite exists in the Southern United States, but recent studies indicate an active peri-domestic life cycle of T. cruzi in Texas. The United States-Mexico border region in Texas displays areas of high poverty and sub-standard housing conditions which are important risk factors for a potential spill-over transmission to a domestic life cycle including humans. The objectives of the study were to examine short- and long-term temporal variation in vector activity and to evaluate the effect of different combinations of attractants on the capture of potential triatomine vectors. We collected local triatomine vectors (all of them identified as Triatoma gerstaeckeri) from a natural habitat in South Texas during the course of a year. The exact time of collection was recorded to examine the timing of flight activity of the triatomine vector. We also conducted a comparative study of the efficiency of 2 commonly used attractants (light and CO2) and the combination of those on the capture rate of Tr. gerstaeckeri. Our study indicates a short season of dispersal of Tr. gerstaeckeri (April/May) and it suggests a unimodal distribution of activity peaking between 2 and 3 hr after sunset. Ultra-violet light served as the main attractant of Tr. gerstaeckeri while CO2 from dry ice did not significantly contribute to the collection of vectors. The pronounced timing of activity in Tr. gerstaeckeri reported in this study contributes to our understanding of the epidemiology of T. cruzi in wildlife and its potential as a Chagas disease vector to humans in the Rio Grande Valley, South Texas.

Spatial and temporal trends of reference crop evapotranspiration and its influential variables in Yangtze River Delta, eastern China

Reference crop evapotranspiration (ETo) is one of the most important links in hydrologic circulation and greatly affects regional agricultural production and water resource management. Its variation has drawn more and more attention in the context of global warming. We used the Penman-Monteith method of the Food and Agriculture Organization, based on meteorological factors such as air temperature, sunshine duration, wind speed, and relative humidity to calculate the ETo over 46 meteorological stations located in the Yangtze River Delta, eastern China, from 1957 to 2014. The spatial distributions and temporal trends in ETo were analyzed based on the modified Mann-Kendall trend test and linear regression method, while ArcGIS software was employed to produce the distribution maps. The multiple stepwise regression method was applied in the analysis of the meteorological variable time series to identify the causes of any observed trends in ETo. The results indicated that annual ETo showed an obvious spatial pattern of higher values in the north than in the south. Annual increasing trends were found at 34 meteorological stations (73.91 % of the total), which were mainly located in the southeast. Among them, 12 (26.09 % of the total) stations showed significant trends. We saw a dominance of increasing trends in the monthly ETo except for January, February, and August. The high value zone of monthly ETo appeared in the northwest from February to June, mid-south area from July to August, and southeast coastal area from September to January. The research period was divided into two stages—stage I (1957–1989) and stage II (1990–2014)—to investigate the long-term temporal ETo variation. In stage I, almost 85 % of the total stations experienced decreasing trends, while more than half of the meteorological stations showed significant increasing trends in annual ETo during stage II except in February and September. Relative humidity, wind speed, and sunshine duration were identified as the most dominant meteorological variables influencing annual ETo changes. The results are expected to assist water resource managers and policy makers in making better planning decisions in the research region.

BAYESIAN HIERARCHICAL ANOVA MODEL OF STOCHASTIC SEASONALITY FOR Diodon holocanthus IN NORTHERN TAIWAN

Detecting seasonal variation in ecological phenomena is not always possible by use of traditional methods. The pattern of seasonality fluctuates because of the stochasticity of environmental factors, correlations among organisms, and human activity. Here, we propose a Bayesian hierarchical analysis of variance (ANOVA) model of stochastic seasonality for detecting the annual fluctuation of seasonality. Using 11-year data recorded monthly at 2 nuclear power plants in northern Taiwan, we examined monthly fluctuations in fish species. To illustrate the performance of the proposed model, we conducted a simulation that reflects the varying seasonality of species. The most dominant species, Diodon holocanthus, exhibited a shift in peak abundance from March to July that the traditional ANOVA model failed to detect. Our results suggest that impingement data obtained from the intakes of power plants are useful in studying the long-term temporal variation of fish species. The proposed model provides an in-depth examination of temporal variation for ecological analysis.