Annual Mean Diurnal Temperature Range Research Articles

Long-term temperature variability and death among stroke patients: A cohort study in central Shandong province, China

Our current understanding of the repercussions stemming from long-term temperature variability (TV) within the broader context of global climate change remains considerably limited. This study aims to investigate the influence of long-term temperature variability on the probability of death and mortality among stroke patients. For this study, a sample of stroke patients aged 40 years and above between 2016 and 2019 was taken from five districts/counties in central Shandong Province. We calculated the standard deviation (SD) of the annual mean daily temperature and the annual mean diurnal temperature range (DTR) obtained from the baseline survey to express the long-term TV. To assess the link between TV exposure and mortality among stroke patients, we utilized the Cox proportional hazards regression method. This statistical method allowed us to estimate the adjusted hazard ratio (HR) and 95 % confidence interval (CI) with regard to the risk of mortality. For stroke patients, there was a correlation between a 1 °C rise in the SD of temperature and an elevated risk of mortality (HR: 1.18, 95 % CI: 1.08–1.29). Additionally, each 1 °C increase in the DTR was associated with a further increase in the risk of death (HR: 1.69, 95 % CI: 1.59–1.79). In patients diagnosed with ischemic and hemorrhagic stroke, DTR was found to be positively associated with the risk of death. Temperature SD was found to be positively associated with the risk of death only in patients with ischemic stroke. Persistent exposure to TV was strongly linked to mortality risk among individuals with stroke. By devoting increased attention to TV, these organizations can develop strategies to mitigate its adverse effects on public health.

Climatic Drivers of Silicon Accumulation in a Model Grass Operate in Low- but Not High-Silicon Soils

Grasses are hyper-accumulators of silicon (Si), which is known to alleviate diverse environmental stresses, prompting speculation that Si accumulation evolved in response to unfavourable climatic conditions, including seasonally arid environments. We conducted a common garden experiment using 57 accessions of the model grass Brachypodium distachyon, sourced from different Mediterranean locations, to test relationships between Si accumulation and 19 bioclimatic variables. Plants were grown in soil with either low or high (Si supplemented) levels of bioavailable Si. Si accumulation was negatively correlated with temperature variables (annual mean diurnal temperature range, temperature seasonality, annual temperature range) and precipitation seasonality. Si accumulation was positively correlated with precipitation variables (annual precipitation, precipitation of the driest month and quarter, and precipitation of the warmest quarter). These relationships, however, were only observed in low-Si soils and not in Si-supplemented soils. Our hypothesis that accessions of B. distachyon from seasonally arid conditions have higher Si accumulation was not supported. On the contrary, higher temperatures and lower precipitation regimes were associated with lower Si accumulation. These relationships were decoupled in high-Si soils. These exploratory results suggest that geographical origin and prevailing climatic conditions may play a role in predicting patterns of Si accumulation in grasses.

Spatiotemporal changes in temperature and precipitation over the Songhua River Basin between 1961 and 2014

The Songhua River Basin is one of the main grain-producing areas in China, and local climate change has had a direct impact on grain production during the past several decades. This study focused on changes in mean and extreme climate conditions in the Songhua River Basin during the period 1961–2014. We founded that the precipitation decreased slightly over most of the basin; however, an increasing occurrence of extreme events was detected in the northern and eastern parts of the basin, especially for the number of very wet days and, correspondingly, how much those days contributed to total precipitation. By contrast, the mean, maximum and minimum temperature values between 1961 and 2014 showed statistically significant positive trends in almost all regions of the basin. The rate of change was greater for minimum temperature than maximum temperature, which resulted in a significant increasing trend for the number of warm nights and an overall decreasing trend in the annual mean diurnal temperature range. Generally, the magnitudes of changes in temperature were more remarkable than the magnitudes of changes in precipitation over the Songhua River Basin. If we take both precipitation and temperature changes into account, the areas sensitive to climate change during the last five decades were in the southern and central parts of the Songhua River Basin.

Effect of climate on provincial-level banana yield in the Philippines

This study assessed the effect of climate on banana yield in the Philippines using provincial level yield data and different climatic variables (i.e. annual rainfall, frequency of wet days, precipitation seasonality, annual mean temperature, temperature seasonality, and annual mean diurnal temperature range) derived from Climate Research Unit – Time Series (CRU-TS) dataset from year 1991–2016. First, trend analysis was applied to the time series of banana yield data for each province to determine presence of linear trend. Then, based on the result of linear trend analysis, multiple regression analysis was used to assess the effect on climate on provincial-level banana yield. Trend analysis showed that 71% of banana producing area in the country experience significant yield trend while multiple regression analysis showed that only 10% of the banana producing areas in the country is significantly affected by climate. Compared to rainfall, temperature variables, specifically temperature seasonality has the greater influence on provincial-level banana yield in the Philippines.

Bioclimatic Extremes Drive Forest Mortality in Southwest, Western Australia

Extreme and persistent reductions in annual precipitation and an increase in the mean diurnal temperature range have resulted in patch scale forest mortality following the summer of 2010–2011 within the Forest study area near Perth, Western Australia. The impacts of 20 bioclimatic indicators derived from temperature, precipitation and of actual and potential evapotranspiration are quantified. We found that spatially aggregated seasonal climatologies across the study area show 2011 with an annual mean of 17.7 °C (± 5.3 °C) was 1.1 °C warmer than the mean over recent decades (1981–2011,- 16.6 °C ± 4.6 °C) and the mean has been increasing over the last decade. Compared to the same period, 2010–2011 summer maximum temperatures were 1.4 °C (31.6 °C ± 2.0 °C) higher and the annual mean diurnal temperature range (Tmax−Tmin) was 1.6 °C higher (14.7 °C ± 0.5 °C). In 2009, the year before the forest mortality began, annual precipitation across the study area was 69% less (301 mm ± 38 mm) than the mean of 1981–2010 (907 mm ± 69 mm). Using Système Pour l'Observation de la Terre mission 5 (SPOT-5) satellite imagery captured after the summer of 2010–2011 we map a broad scale forest mortality event across the Forested study area. This satellite-climatology based methodology provides a means of monitoring and mapping similar forest mortality events- a critical contribution to our understanding the dynamical bioclimatic drivers of forest mortality events.

Basic Features of Climate Change in North China during 1961–2010

The spatial and temporal variations of some important near-surface climate parameters and extreme climate events in North China during 1961–2010 are analyzed by using 94 meteorological stations’ data in the study area. Results show that the annual mean surface air temperature in North China increased at the rate of 0.36°C per decade, higher than the national average in the same period. Increasing was particularly significant since the mid-1980s, with maximum increase in the middle and northeastern parts of Inner Mongolia. Increasing rate of the annual mean minimum temperature is much higher than that of the maximum temperature, which results in the decrease of the annual mean diurnal temperature range. Noticeable decrease is also observed in the frequency of cold wave. Annual precipitation shows a slight decreasing trend, with more pronounced decrease in southern Shanxi and eastern Hebei provinces, which is mainly represented as decreasing in contribution rates of rainstorm and heavy storm in flood-season (May to September). During 1961–2010, North China is characterized by a noticeable reduction in annual extreme precipitation, and an increase in high-temperature days over most parts, as well as more frequent droughts. There are remarkable reductions in annual sunshine duration and mean wind speed, associated with the most significant reduction of mean wind speed in midwestern and eastern parts of Inner Mongolia. Meanwhile, North China has experienced a noticeable decrease/increase in annual mean sanddust/haze days during the study period. However, there is no significant trend in fog days, except a pronounced decrease since the 1990s. CitationGuo, W.-L., H.-B. Shi, J.-J. Ma, et al., 2013: Basic features of climate change in North China during 1961–2010. Adv. Clim. Change Res.,4(2), doi: 10.3724/SP.J.1248.2013.073.

Temperature and precipitation of Alaska: 50 year trend analysis

Temperature and precipitation records from 1949 to 1998 were examined for 25 stations throughout the State of Alaska. Mean, maxima, and minima temperatures, diurnal temperature range, and total precipitation were analyzed for linear trends using least squares regressions. Annual and seasonal mean temperature increases were found throughout the entire state, and the majority were found to be statistically significant at the 95% level or better. The highest increases were found in winter in the Interior region (2.2 °C) for the 50 year period of record. Decreases in annual and seasonal mean diurnal temperature range were also found, of which only about half were statistically significant. A state-wide decrease in annual mean diurnal temperature range was found to be 0.3 °C, with substantially higher decreases in the South/Southeastern region in winter. Increases were found in total precipitation for 3 of the 4 seasons throughout most of Alaska, while summer precipitation showed decreases at many stations. Few of the precipitation trends were found to be statistically significant, due to high interannual variability. Barrow, our only station in the Arctic region, shows statistically significant decreases in annual and winter total precipitation. These findings are largely in agreement with existing literature, although they do contradict some of the precipitation trends predicted by the CO2-doubling GCM’s.