Differences In Seasonal Variation Research Articles

Relationships between meteorological parameters and criteria air pollutants in three megacities in China

Meteorological conditions play a crucial role in ambient air pollution by affecting both directly and indirectly the emissions, transport, formation, and deposition of air pollutants. In this study, the relationships between meteorological parameters and ambient air pollutants concentrations in three megacities in China, Beijing, Shanghai, and Guangzhou were investigated. A systematic analysis of air pollutants including PM2.5, PM10, CO, SO2, NO2, and O3 and meteorological parameters including temperature, wind speed (WS), wind direction (WD) and relative humanity (RH) was conducted for a continuous period of 12 months from March 2013 to February 2014. The results show that all three cities experienced severe air quality problems. Clear seasonal trends were observed for PM2.5, PM10, CO, SO2 and NO2 with the maximum concentrations in the winter and the minimum in the summer, while O3 exhibited an opposite trend. Substantially different correlations between air pollutants and meteorological parameters were observed among these three cities. WS reversely correlated with air pollutants, and temperature positively correlated with O3. Easterly wind led to the highest PM2.5 concentrations in Beijing, westerly wind led to high PM2.5 concentrations in Shanghai, while northern wind blew air parcels with the highest PM2.5 concentrations to Guangzhou. In Beijing, days of top 10% PM2.5, PM10, CO, and NO2 concentrations were with higher RH compared to days of bottom 10% concentrations, and SO2 and O3 showed no distinct RH dependencies. In Guangzhou, days of top 10% PM2.5, PM10, CO, SO2, NO2 and O3 concentrations were with lower RH compared to days of bottom 10% concentrations. Shanghai showed less fluctuation in RH between top and bottom 10%. These results confirm the important role of meteorological parameters in air pollution formation with large variations in different seasons and geological areas. These findings can be utilized to improve the understanding of the mechanisms that produce air pollution, enhance the forecast accuracy of the air pollution under different meteorological conditions, and provide effective measures for mitigating the pollution.

Spatial distribution, sources and ecological risk assessment of polycyclic aromatic hydrocarbons in surface seawater from Yangpu Bay, China

The occurrence of 14 polycyclic aromatic hydrocarbons (PAHs) listed by the United States Environmental Protection Agency was investigated in surface seawater of Yangpu Bay, China in November 2013 (winter) and May 2014 (summer). Seventy-two samples were collected from 12 sampling sites. The total concentrations of PAHs in Yangpu Bay showed obvious variations in different seasons, which varied from 582.8 to 2208.3ngL−1 in winter and 952.4 to 1201.7ngL−1 in summer, respectively. Two-ring PAHs accounted for more than 91.6% of total PAHs in winter, and three-ring PAHs were dominant with 81.6% of total PAHs in summer. Molecular indices analyses indicated that the main source of PAHs in Yangpu Bay could be petrogenic contamination. The ecological risk assessment by Risk quotients (RQNCs and RQMPCs) showed a potential ecological risk of PAHs in Yangpu Bay, indicating a close attention should be paid to pollution of PAHs in the coastal area of Yangpu.

Indo-China monsoon indices.

Myanmar and Thailand often experience severe droughts and floods that cause irreparable damage to the socio-economy condition of both countries. In this study, the Southeastern Asian Summer Monsoon variation is found to be the main element of interannual precipitation variation of the region, more than the El Niño/Southern Oscillation (ENSO). The ENSO influence is evident only during the boreal spring season. Although the monsoon is the major factor, the existing Indian Monsoon Index (IMI) and Western North Pacific Monsoon Index (WNPMI) do not correlate well with the precipitation variation in the study regions of Southern Myanmar and Thailand. Therefore, a new set of indices is developed based on the regional monsoon variations and presented here for the first time. Precipitation variations in Southern Myanmar and Thailand differ as well as the elements affecting the precipitation variations in different seasons. So, separate indices are proposed for each season for Southern Myanmar and Thailand. Four new monsoon indices based on wind anomalies are formulated and are named as the Indochina Monsoon Indices. These new indices correlate better with the precipitation variations of the study region as compared to the existing IMI and WNPMI.

Work Ergonomic Analysis at the Quality Material Inspection Station in a Graphic Industry

This paper is based on an ergonomic analysis of quality review station in a printing company in the southernmost of Brazil. Analyses were made on the issues of environmental comfort, injury risks and pain causes identified by workers in the sector, five women. After analyzing the critical points of acoustic and thermal comfort, concerning temperature variation in different seasons, not taking regular breaks to rest, which is causing muscle fatigue in the joints of the upper limbs, and were appointed to conduct task not directly related to their activity, which increases significantly the carrying out time to reviewing and so left no time for breaks. They take painkillers and anti-inflammatory often. Suggestions were made to minimize the risk of accidents and musculoskeletal injuries, improve working conditions as comfort reduced time to perform the task and include rest breaks during working hours without loss to production. Including pauses enables stop taking medicines.

14-1 Gender differences in seasonal variation of risk factors for acute myocardial infarction in eastern Taiwan

14-1 Gender differences in seasonal variation of risk factors for acute myocardial infarction in eastern Taiwan

Characterization of fine particulate black carbon in Guangzhou, a megacity of South China

Continuous measurement of fine particulate black carbon (BC) was conducted at an urban site of Guangzhou in South China from December 2007 to December 2008. The daily average BC concentrations ranged from 0.6 to 20.5μg m−3, with an average value of 4.7μg m−3, which was substantially higher than those observed in the urban areas of other developed countries. Diurnal fluctuations of BC were marked with two peaks, one in the morning rush hour (08:00LT) and the other in the late evening hour (21:00–22:00LT), while the lowest BC concentrations were observed in the afternoon. Ambient BC concentrations displayed significant seasonal and diurnal variations with higher values in winter and spring, followed by lower concentrations during autumn and summer. Wind speed, wind direction and temperature were important meteorological factors that affected BC concentrations. A clearly negative correlation (r=−0.50, p<0.01) between BC concentrations and wind speed was found during the study period. A specific investigation was conducted to determine the relationship between optical BC and thermal–optical–reflectance elemental carbon (TOR EC) in distinct seasons. Although significant correlations between BC and EC were obtained (r>0.92, p<0.01), the regression slopes (ΔBC/ΔEC) slightly deviated from each other with values of 0.79, 1.18, and 0.81 in winter, spring and summer, respectively, possibly due to the distinct mixing states and source variations in different seasons. The calculated experimental attenuation coefficient showed a higher value (19.3m2g−1) in Guangzhou than the one recommended for typical Aethalometer measurements.

Elevation–diversity patterns through space and time: ant communities of the Maloti‐Drakensberg Mountains of southern Africa

AbstractAimPatterns of biological diversity are often investigated across space but little work has attempted to explore the consistency of such observations through time. Here, our aim was to understand the patterns of diversity for a functionally critical taxon, the ants (Hymenoptera: Formicidae), through space and time using an extensive dataset collected across an elevational gradient. In addition, we evaluated the importance of two key postulated drivers of elevational diversity patterns: temperature and available area.LocationThe Maloti‐Drakensberg Mountains of southern Africa.MethodsWe sampled epigaeic ant communities biannually for 7 years (2006–2012) at eight different elevational sites. We then used an information theoretic approach combined with generalized linear mixed models to: (1) describe diversity patterns through space and time; (2) assess the importance of different abiotic drivers; and (3) understand how much spatio‐temporal variation can be explained by these drivers. Simple regression approaches were also used to test for differences in seasonal variation along the elevational gradient.ResultsWe found clear mid‐elevational peaks of species density and evenness measures. Abundance patterns were complex. The spatial distributions of all three metrics changed across seasons and years. Temperature variables had important roles in explaining both species density and abundance patterns, whilst species density was also influenced by available area. In conjunction, we found much greater seasonal variability in species density at low elevations. This variation was independent of differences in species pool size.Main conclusionsWe found patterns of ant diversity that are strongly modulated by temporal change. There was a consistent and strong signature of seasonality on the elevation–diversity patterns of the ants, whilst annual changes throughout the study period had a weaker influence. We conclude that both spatial and temporal patterns are driven primarily by temperature, with only a weak influence of available elevational area. This study is the first to describe the spatio‐temporal distribution of a suite of community‐level metrics along an elevational gradient and implies that temporal variation should be considered more carefully in studies of invertebrate diversity, particularly with respect to elevation and the mechanisms that may be maintaining diversity patterns.

Sex-Specific Seasonal Change in Body Mass in Two Species of Vespertilionid Bats

In most mammals, reproductive cost differs between males and females in timing and duration because of the different sex-specific energy allocation strategies to maximize fitness. The differences in reproductive strategy adopted by sexes may result in differences in seasonal variation of body mass. Here seasonal variations in body mass are discussed for two species of vespertilionid bats: Daubenton's bat (Myotis daubentonii) and Savi's pipistrelle (Hypsugo savii). Both species were observed to have a seasonal variability in body conditions, which was sex dependent. In late spring and for a given forearm length, females were heavier than males, but differences were small in late summer. Furthermore, female'’s body mass decreased during late spring and summer likely to support the energy requirement for lactation, while male's mass did not change (H. savii) or slightly increase (M. daubentonii) over the same period. On the contrary male M. daubentonii depleted body fat reserves during early autumn, likely because of the energy expenditure to increase mating opportunities. Our results suggest that seasonal changes in body condition in hibernating bats may reflect the differences in reproductive strategies between sexes.

Spatial and Seasonal Variation of Dissolved Organic Carbon (DOC) Concentrations in Irish Streams: Importance of Soil and Topography Characteristics

Dissolved organic carbon (DOC) concentrations have increased in many sites in Europe and North America in recent decades. High DOC concentrations can damage the structure and functions of aquatic ecosystems by influencing water chemistry. This study investigated the spatial and seasonal variation of DOC concentrations in Irish streams across 55 sites at seven time occasions over 1year (2006/2007). The DOC concentrations ranged from 0.9 to 25.9mg/L with a mean value of 6.8 and a median value of 5.7mg/L and varied significantly over the course of the year. The DOC concentrations from late winter (February: 5.2±3.0mg/L across 55 sites) and early spring (April: 4.5±3.5mg/L) had significantly lower DOC concentrations than autumn (October: mean 8.3±5.6mg/L) and early winter (December: 8.3±5.1mg/L). The DOC production sources (e.g., litterfall) or the accumulation of DOC over dry periods might be the driving factor of seasonal change in Irish stream DOC concentrations. Analysis of data using stepwise multiple linear regression techniques identified the topographic index (TI, an indication of saturation-excess runoff potential) and soil conditions (organic carbon content and soil drainage characteristics) as key factors in controlling DOC spatial variation in different seasons. The TI and soil carbon content (e.g., soil organic carbon; peat occurrence) are positively related to DOC concentrations, while well-drained soils are negatively related to DOC concentrations. The knowledge of spatial and seasonal variation of DOC concentrations in streams and their drivers are essential for optimum riverine water resources management.

PBDEs, hydroxylated PBDEs and methoxylated PBDEs in bivalves from Beijing markets

The structural analogues of polybrominated diphenyl ethers (PBDEs), hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) have been attracting increasing concern in recent years. Five bivalve species (blue mussel, short-necked clam, surf clam, ark shell and razor clam) were collected from Beijing markets, and the concentrations of seven PBDEs, four OH-PBDEs and fourteen MeO-PBDEs in the bivalves were measured. The seasonal variations of these three types of polybrominated compound in blue mussels were also monitored. The results indicate that the levels of ΣPBDEs in this study were comparable to those in short-necked clams from Liaodong Bay, China, with BDE47 as the dominant congener. For the ortho-MeO-PBDEs, 6-MeO-BDE47 was found at higher concentrations than the others, while for the meta- and para-MeO-PBDEs, 4′-MeO-BDE17 was found at higher concentrations. 6-OH-BDE-47 was the most abundant congener among the 4 measured OH-PBDEs, followed by 6-OH-BDE-137 and 6-OH-BDE-85. The levels of OH-PBDEs and MeO-PBDEs in bivalves from Beijing markets were much lower than the corresponding compounds in blue mussels from the Baltic Sea. In the blue mussels collected in April, June and September of 2012, apparent seasonal variations were observed for these three types of polybrominated compounds, but the acidic components displayed different trends from the neutral components, with PBDEs and MeO-PBDEs showing the highest concentrations in June, while OH-PBDEs had the lowest concentrations in June. This difference in seasonal variations between the neutral components and the acidic components may be explained by their different sources and transformation/elimination mechanisms.

Potential Predictability of North American Surface Temperature. Part I: Information-Based versus Signal-To-Noise-Based Metrics

Abstract In this study, the potential predictability of the North American (NA) surface air temperature was explored using information-based predictability framework and Ensemble-Based Predictions of Climate Changes and their Impacts (ENSEMBLES) multiple model ensembles. Emphasis was put on the comparison of predictability measured by information-based metrics and by the conventional signal-to-noise ratio (SNR)-based metrics. Furthermore, the potential predictability was optimally decomposed into different modes by maximizing the predictable information (equivalent to the maximum of SNR), from which the most predictable structure was extracted and analyzed. It was found that the conventional SNR-based metrics underestimate the potential predictability, in particular in these areas where the predictable signals are relatively weak. The most predictable components of the NA surface air temperature can be characterized by the interannual variability mode and the long-term trend mode. The former is inherent to tropical Pacific sea surface temperature (SST) forcing such as El Niño–Southern Oscillation (ENSO), whereas the latter is closely associated with the global warming. The amplitude of the two modes has geographical variations in different seasons. On this basis, the possible physical mechanisms responsible for the predictable mode of interannual variability and its potential benefits to the improvement of seasonal climate prediction were discussed.

Seasonality of suicide deaths in Serbia, 1990-2012

Background: In the period from 1990 to 2012, there were 32,855 suicides registered in Serbia, i.e. an average of 1428 deaths per year (18.9 per 100.000 inhabitants). The suicides were the most frequent in the early 1990s, less frequent during the 2000s, and least frequent in the last three years of the observed period (2010-2012 - an average of 1237 suicides per year). Objective: The goal of this paper is to evaluate the seasonal variations of suicides in Serbia in the period of 1990-2012, their changes, as well as the accordance with findings from other countries. Method: In the paper are used "classical" statistical methods of evaluating cyclical variations (?2-test, Edwards' test) as well as some frequently used newer methods (e.g. the peak-low ratio). It also introduces a new indicator of the intensity of monthly variations in suicides (the magnitude of trimester variations of /12/ moving consecutive months index - the MtMV index). Seasonality of suicides is also observed by sex. Results: The results of the research of seasonality confirm that certain cyclical variations in mortality due to suicide are also present in Serbia. Observed by season, suicides are most frequent in spring and summer and less in winter. The cyclical nature was also clearly confirmed by month. Suicides are most frequent in "warm" months (April-August) and far less frequent in "cold" months (December-February). By month, suicides are most frequent in May, while the maximal average number of suicides per day was calculated for June (21 % higher than the average for 1990-2012). December is singled out as the month with the lowest number as well as lowest daily average of suicides (25 % lower than the average). Conclusion: The cyclical nature of suicides is clearly notable during the entire observed period and no significant fluctuations or decrease in the intensity of the variation were observed. Regardless of the method of analysis, the resulting conclusions are identical regarding the cyclical nature of the variations and the temporal characteristics of suicides in Serbia at the end of the 20th and the beginning of the 21st century. At the aggregate level there are no significant differences in seasonal variations of suicides committed by men and women. Changes also developed in parallel and in the same direction for both sexes.

Differences in seasonal variations in the patterns of diurnal earthquake periodicity in the southern and northern hemispheres

Seasonal variations in the form of diurnal periodicity are compared in three regions of the world, two of which (Alaska and Japan) are located in the Northern Hemisphere and one (New Zealand) is in the Southern Hemisphere. It is found that, in the Northern Hemisphere, the duration of the night interval of an increased number of earthquakes in December is greater than in June, while in the Southern Hemisphere it is smaller. The intra-annual character of variations in the form of diurnal earthquake periodicity agrees with the seasonal variations in the length of the day.

Spatial differences in seasonal variation of the upper-tropospheric jet stream in the Northern Hemisphere and its thermal dynamic mechanism

NCEP/NCAR reanalysis daily data from 1951 to 2008 are used in this study to reveal the spatial-asymmetric features in the seasonal variation of the upper-tropospheric jet stream (UTJS) and its thermal dynamic forcing mechanism. The jet occurrence percentage distribution of the UTJS demonstrates a spiral-like pattern in winter, but it is quasi-annular in summer. The jet occurrence percentage in the Eastern Hemisphere is larger than that in the Western Hemisphere, and its maximum area is located further south. The polar front jet stream (PJS) and subtropical jet stream (SJS) can be distinguished over the Northern Africa and Asian regions, whereas only one jet stream can be observed over the Western Pacific and Atlantic Ocean. Furthermore, a single peak pattern is found in the seasonal variation of the SJS occurrence frequency with the highest jet occurrence appearing in winter and the lowest in summer, while a double peak pattern is observed in the seasonal variation of the PJS occurrence, i.e., the jet occurrence reaches its peaks in autumn and spring for the PJS. Based on the thermal wind theory, air temperature gradient and atmospheric baroclinicity are calculated and compared with the jet occurrence variation to explore the thermal dynamic forcing mechanism for the UTJS variation. In addition, synoptic-scale transports of eddy heat and momentum are also calculated. The results indicate that the SJS variation is primarily determined by the air temperature gradient and atmospheric baroclinicity, while the PJS variation is under great influence of the transport of eddy heat and momentum over Northern Africa and East Asia. The UTJS variation over the area from 140E to 70W cannot be well individually explained by the air temperature gradient and atmospheric baroclinicity. Further analysis indicates that UTJS variation over this area is largely under control of combined effect of the transport of eddy heat and momentum as well as the atmospheric baroclinicity.

Effects of the introduction of rice on evapotranspiration in seasonal wetlands

AbstractLand use changes in wetland areas can alter evapotranspiration, a major component of the water balance, which eventually affects the water cycle and ecosystem. This study assessed the effect of introduced rice‐cropping on evapotranspiration in seasonal wetlands of northern Namibia. By using the Bowen ratio–energy balance method, measurements of evapotranspiration were performed over a period of 2.5 years at two wetland sites—a rice field (RF) and a natural vegetation field (NVF)—and at one upland field (UF) devoid of surface water. The mean evapotranspiration rates of RF (1.9 mm daytime−1) and NVF (1.8 mm daytime−1) were greater than that in UF (1.0 mm daytime−1). RF and NVF showed a slight difference in seasonal variations in evapotranspiration rates. During the dry season, RF evapotranspiration was less than the NVF evapotranspiration. The net radiation in RF was less in this period because of the higher albedo of the non‐vegetated surface after rice harvesting. In the early growth period of rice during the wet season, evapotranspiration in RF was higher than that in NVF, which was attributed to a difference in the evaporation efficiency and the transfer coefficient for latent heat that were both affected by leaf area index (LAI). Evapotranspiration sharply negatively responded to an increase in LAI when surface water is present according to sensitivity analysis, probably because a higher LAI over a surface suppresses evaporation. The control of LAI is therefore a key for reducing evaporation and conserving water. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Temporal variation of atmospheric CH4 and the potential source regions at Waliguan, China

We used a revised dataset of the atmospheric CH4 mixing ratios that were continuously measured at Mount Waliguan Baseline Observatory of western China during 2002–2006 to study the temporal variations and the potential sources regions of ambient CH4. Approximately 58% observed values were filtered as background data by applying a robust local regression mathematic procedure. The median, 10% and 90% percentiles of CH4 background mixing ratios were 1831.8, 1820.7 and 1843.5 ppb (10−9 mol mol−1), respectively; the atmospheric CH4 time series showed large variations with a fluctuation of 200 ppb (maximum minus minimum), but the background CH4 exhibited a much smaller variation (about 38 ppb), indicating strong impacts from local or regional sources and sinks. Ambient CH4 displayed significant diurnal variations in different seasons during 2002–2006, as was the combined result of changes of nearby sources/sinks and local meteorological circulation. The averaged CH4 seasonal cycle showed minimum in spring and winter, maximum in summer (from June to August), as is completely opposite to that observed at Mauna Loa and Niwot Ridge. The incongruous variation should be attributed to enhancing regional/local sources (e.g., herd) around the site as well as the dominant air flow from the polluted north/northeastern region (e.g., Xining and Lanzhou city) in summer. Another possible reason is, compared to Mauna Loa and Niwot Ridge, the photochemical reaction at Waliguan is weaker. An analysis of 5 d back-trajectory (500 hPa) showed that the episode of high CH4 mixing ratios was associated with advection from the heavily populated regions east or southeast (e.g., Xining and Lanzhou) of Waliguan and northwest of Qinghai via Ge’ermu urban area where growing industrial activities as well as crops residue burning provide large sources of CH4, suggesting a large source area; the low values were observed most frequently when air masses originated from the sparsely populated Tibet and south of Qinghai and Xinjiang Uygur Autonomous Region (XUAR). Additionally, atmospheric CH4 would be enhanced when air masses originated from Ningxia and northwest of Gansu areas (mainly growing rice) along the Yellow river region, especially in summer, suggesting agriculture source of CH4. Our study helps to accurately estimate sources and sinks of CH4, and thus is significant for understanding greenhouse effect over a regional scale and predicting global change in future.

Effects of forest gaps on some microclimate variables in Castanopsis kawakamii natural forest

The objective of this study was to understand the effects of forest gap and variations in different seasons, gap size, locations and diurnal variations on forest microclimate and soil water content. Spatial and temporal distribution features of air temperature (TA), soil temperature (TS), relative humidity (h) and soil water content (Ψ) were measured in Castanopsis kawakamii natural forest gaps created by a severe typhoon or fallen dead trees. The results showed that: (1) the variations of TA, h, and TS in four seasons were extremely significant. The variations of Ψ in four seasons were extremely significant except for those between spring and summer. (2) The diurnal variations of TA and TS were expressed with a single peak curve. The diurnal variations of h and Ψ presented a high-low-high trend. (3) The variations of TA, h, and TS were extremely significant among the large, medium and small gaps in C. kawakamii natural forest. Medium gaps had the highest TA and the lowest h while small gaps were just contrary to medium gaps. The variations of Ψ were extremely significant for large, medium and small gaps except those between the medium and large gaps. (4) The TA, h, TS and Ψ were decreased from the gap center, canopy gap, expanded gap to understory. These results will help further our understanding of the abiotic and consequent biotic responses to gaps in the mid-subtropical broadleaved forests, which also provide a theoretical basis for the scientific management and population restoration of C. kawakamii natural forest.

Modeling Seasonal Variation in Tourism Flows with Climate Variables

The purpose of this article is to model and forecast the seasonal variation, the fluctuations in tourist numbers from season to season in Australian inbound holiday tourism, using climate variables such as maximum temperature, humidity, and hours of sunshine. For estimation purposes this study uses quarterly data on arrivals from the US, UK, Japan, and New Zealand to Australia from September 1975 to September 2009. Seasonal variation, which is the respective and predictable movement of visitation around the trend line, was first extracted from the quarterly holiday tourist arrivals time-series using the Basic Structural Model (BSM) approach. Subsequently, the influence of climate variables on seasonal variation in different seasons was identified using the average euclidean minimum distance (AD) statistics. The AD statistics show that climate variables shape the characteristic of seasonal variation of tourism flows but the effect tends to vary between seasons and countries. A time-series model was estimated with climate variables to forecast seasonal variation. The forecasting comparison result shows that climate variables improve the forecasting performance. The approach can be replicated to help destination managers and forecasters determine if climate variables influence tourism flows between other origins and destinations globally.

Epidemiologic Features of Parainfluenza Virus Type 1, 2 and 3 Infection in Seoul and a Neighboring Area, 2008-2011

Background Parainfluenza virus (PIV) is a significant cause of acute respiratory infections. Epidemiological information on PIV infection could be very helpful for patient management. The aim of this study was to investigate the epidemiology of PIV infection in Seoul and a neighboring area with regard to PIV type. Methods The diagnosis of PIV infection was made by virus isolation. The R-mix Too cell system (Diagnostic Hybrids, Inc., Athens, OH, USA) and D3 Ultra DFA Respiratory Virus Screening & ID kits (Diagnostic Hybrids, Inc.) were used for virus culture and identification. The medical records of patients with positive virus cultures were reviewed retrospectively. Results Seven hundred and ten PIV viruses (5.6%) were isolated from 12,723 specimens. The number of subjects with PIV type III, I and II was 357, 304 and 49, respectively. PIV infection showed a peak incidence in the first year of life regardless of subtypes. The most common diagnosis among all PIV subtypes was pneumonia. Lower respiratory tract infections constituted the majority (76.3%) of PIV infections. The most common diagnosis of PIV type I and II was croup and that of PIV type III was pneumonia. A difference in seasonal variation between subtypes was observed. PIV I (62.2%) was mainly isolated from July to September while PIV type III (86.8%) was isolated from April to July. Conclusion Lower respiratory infection was most commonly found in hospitalized patients with PIV infection. Clinical features of PIV infection were similar those seen in Western PIV reports, with the exception of the seasonal outbreak pattern.

Effect of altitude and latitude on surface air temperature across the Qinghai-Tibet Plateau

The correlation between mean surface air temperature and altitude is analyzed in this paper based on the annual and monthly mean surface air temperature data from 106 weather stations over the period 1961–2003 across the Qinghai-Tibet Plateau. The results show that temperature variations not only depend on altitude but also latitude, and there is a gradual decrease in temperature with the increasing altitude and latitude. The overall trend for the vertical temperature lapse rate for the whole plateau is approximately linear. Three methods, namely multivariate composite analysis, simple correlation and traditional stepwise regression, were applied to analyze these three correlations. The results assessed with the first method are well matched to those with the latter two methods. The apparent mean annual near-surface lapse rate is −4.8 °C /km and the latitudinal effect is −0.87 °C /olatitude. In summer, the altitude influences the temperature variations more significantly with a July lapse rate of -4.3°C /km and the effect of latitude is only −0.28°C /olatitude. In winter, the reverse happens. The temperature decrease is mainly due to the increase in latitude. The mean January lapse rate is −5.0°C /km, while the effect of latitude is −1.51°C /olatitude. Comparative analysis for pairs of adjacent stations shows that at a small spatial scale the difference in altitude is the dominant factor affecting differences in mean annual near-surface air temperature, aided to some extent by differences of latitude. In contrast, the lapse rate in a small area is greater than the overall mean value for the Qinghai-Tibet Plateau (5 to 13°C /km). An increasing trend has been detected for the surface lapse rate with increases in altitude. The temperature difference has obvious seasonal variations, and the trends for the southern group of stations (south of 33° latitude) and for the more northerly group are opposite, mainly because of the differences in seasonal variation at low altitudes. For yearly changes, the temperature for high-altitude stations occurs earlier clearly. Temperature datasets at high altitude stations are well-correlated, and those in Nanjing were lagged for 1 year but less for contemporaneous correlations. The slope of linear trendline of temperature change for available years is clearly related to altitude, and the amplitude of temperature variation is enlarged by high altitude. The change effect in near-surface lapse rate at the varying altitude is approximately 1.0°C /km on the rate of warming over a hundred-year period.