Maximum, Minimum, and Daily Air Temperature Range in Orchards: What Do Observations Reveal?

This study was designed to better understand vegetation’s impact on air maximum (Tmax), minimum (Tmin), and daily temperature range (DTR), as well as seasonality and variability. We selected a flat, under synoptic-scale, northern Serbian region with an operational network of automated weather stations (AWS) for the study. Data were collected directly from the eighteen AWSs placed in the orchard canopy during 2013–2018. Meteorological data, plant phenological data in the form of the BBCH scale, and orchards’ soil characteristics data were collected. Environmental factors influencing the temperature were classified as static (slow or unchangeable) and dynamic (fast-changing). The impact of both factors on maximum, minimum, and daily temperature range and its variability were analyzed. Results show that static factors (like soil texture) affect the annual variation of Tmax, Tmin, and DTR rather than its variability over the season. The dynamic factors, mainly coming from the plant’s phenology, substantially affected the seasonal variability of these variables. Studies like this suffer from missing data and sparse spatial coverage by the AWS network. Therefore, the alternatives of orchard micrometeorological data, nearest climatological station, and ERA5-Land reanalysis data are tested. Both data sets showcased limitations in their applicability, while reanalysis data deviated more from the in-situ measurements, both seasonally and regionally.

Lichens buffer tundra microclimate more than the expanding shrub Betula nana

Background and Aims In tundra systems, soil-borne lichens are often the dominant groundcover organisms, and act to buffer microclimate extremes within or at the surface of the soil. However, shrubs are currently expanding across tundra systems, potentially causing major shifts in the microclimate landscape. Methods Here, we compared soil temperature and moisture underneath the dwarf birch Betula nana and seven abundant lichen species in subalpine Norway. We also examined mixtures of lichens and dwarf birch, an intermediate phase of shrubification, and measured several functional traits relating to microclimate. Key Results We found that all lichen species strongly buffered the daily temperature range, on average reducing maximum temperatures by 6.9 °C (± 0.7 SD) and increasing minimum temperatures by 1.0 °C (± 0.2 SD) during summer. The dwarf birch had a much weaker effect (maximum reduced by 2.4 °C ± 5.0 SD and minimum raised by 0.2 °C ± 0.9 SD). In species mixtures, the lichen effect predominated, affecting temperature extremes by more than would be expected from their abundance. Lichens also tended to reduce soil moisture, which could be explained by their ability to intercept rainfall. Our trait measurements under laboratory conditions suggest that, on average, lichens can completely absorb a 4.09 mm (± 1.81 SD) rainfall event, which might be an underappreciated part of lichen-vascular plant competition in areas where summer rainfall events are small. Conclusions In the context of shrubification across tundra systems, our findings suggest that lichens will continue to have a large effect on microclimate until they are fully excluded, at which point microclimate extremes will increase greatly.

Abstract P644: Average Daily Temperature Fluctuation and Hospitalizations and 30-Day Mortality for Stroke and AMI

Background: Daily average temperature is associated with increased hospitalizations and mortality for vascular conditions, but it is unclear if daily temperature variation is also associated with these outcomes. We assessed the relationship of daily temperature fluctuations with stroke and AMI hospitalizations and mortality in the elderly. Methods: We identified fee-for-service Medicare beneficiaries aged ≥65 y with a primary discharge diagnosis of ischemic stroke or AMI in 2014-2015. Daily temperature data from the National Centers for Environmental Information were linked with Medicare beneficiary data by county and admission date. We fit a Poisson model for the relationship between daily temperature range (county daily maximum minus minimum) and 30-day hospitalizations, adjusted for season and patient demographics. Logistic regression assessed 30-day mortality, adjusted for season, patient demographics, and clinical characteristics. Overall and NOAA climate region-stratified relationships were assessed. Results: There were 311,213 unique stroke hospitalizations (mean age 78.8 y, 53% women, 84% White) and 274,703 for AMI (mean age 77.6 y, 45.4% women, 86% White). The national hospitalization rate per 100,000 beneficiary-years was 735 for stroke and 639 for AMI. Thirty-day mortality was 12.0% for stroke and 12.8% for AMI. Each 1 o F increase in daily temperature range was associated with a 1.26 percentage point (95% CI 1.09-1.44) increase in stroke and a 1.48 percentage point (95% CI 1.43-1.53%) increase in AMI hospitalizations and varied by climate region (figure). Daily temperature range had little influence on stroke or AMI mortality (both OR 1.00, 95% CI 1.00-1.00). Conclusions: Daily temperature fluctuations were associated with increased hospitalizations for stroke and AMI. Additional research is needed to understand meteorological effects on vascular events to inform prevention efforts for vulnerable populations.

Increases in Biogenic Volatile Organic Compound Concentrations Observed after Rains at Six Forest Sites in Non-Summer Periods

Since biogenic volatile organic compounds (BVOCs) are important precursors of ozone, the monitoring of the BVOC concentration distributions is needed. In general, forest BVOC concentrations increase in summer as well as in other seasons. This study aims to detect temporally sporadic increases in BVOC concentrations in the non-summer months and to analyze the occurring climatic conditions. Using a uniform sampling system and shared gas chromatography–mass spectrometry, the concentrations of isoprene and monoterpenes in six Japanese forests were observed approximately once a month for 3 years. Using the observed data, the relations between the BVOC concentration increases and meteorological factors were evaluated. Twenty instances of temporal increases in BVOC concentrations were observed. These mainly occurred in spring for isoprene and in autumn for monoterpenes. Most of the increases in the non-summer months were observed after a rainfall event, when the daily temperature range was large, suggesting that wind, rain, and a rapid diurnal temperature rise could be factors in the non-summer months. Thus, the network monitoring of BVOC concentrations might be effective for understanding the effects of factors other than temperature, and the mechanisms and frequency of the temporal increases, on the BVOC concentrations in various forests.

Influence of Canopy Cover on Surface Temperature

Trees affect the microclimate, which influences thermal comfort and ecosystem processes. This study investigated the influence of the canopy cover on daily maximum and minimum temperatures. The data are from a collaborative database, and each measurement consists of the minimum and maximum temperatures under the canopy and in an open adjacent area over a 24-hour period. Paired sample t-tests indicated that the canopy decreased the maximum and minimum daily temperatures and narrowed the daily temperature range. Multiple regression showed that the canopy cover percentage decreased the maximum daily temperatures, and this effect was greater in rural areas than in urbanized areas. Another multiple regression indicated that the canopy cover percentage and the distance to the edge of the canopy decreased the daily temperature range. An independent sample t-test also indicated that the effect of the canopy on the daily temperature range was higher in rural areas when analysed by parametric and non-parametric tests but not when measured by a robust test. Other independent sample t-tests indicated that the distance from a light source also decreased the canopy effect on the minimum daily temperature and the daily temperature range. The main plausible underlying processes include the canopy shade and wind insulation, litter insulation of the ground surface, heat pumps through evapotranspiration and lateral heat fluxes from light bulbs and other anthropogenic sources, especially in urbanized areas. These results provide a greater understanding of the effects of arborization in rural and urban ecosystems, as well as their respective benefits to human communities.

Comparing Measured Incoming Shortwave and Longwave Radiation on a Glacier Surface with Estimated Records from Satellite and Off-Glacier Observations: A Case Study for the Forni Glacier, Italy

The development of methods for quantifying meltwater from glaciated areas is very important for better management of water resources and because of the strong impact of current and expected climate change on the Alpine cryosphere. Radiative fluxes are the main melt-drivers, but they can generally not be derived from in situ measures because glaciers are usually located in remote areas where the number of meteorological stations is very low. For this reason, focusing, as a case study, on one of the few glaciers with a supraglacial automatic weather station (Forni Glacier), we investigated methods based on both satellite records and off-glacier surface observations to estimate incoming short- and long-wave radiation at the glacier surface (SWin and LWin). Specifically, for SWin, we considered CM SAF SARAH satellite gridded surface solar irradiance fields and data modeled by cloud transmissivity parametrized from both CM SAF COMET satellite cloud fractional cover fields and daily temperature range observed at the closest off-glacier station. We then used the latter two data sources to derive LWin too. Finally, we used the estimated SWin and LWin records to assess the errors obtained when introducing estimated rather than measured incoming radiation data to quantify glacier melting by means of an energy balance model. Our results suggest that estimated SWin and LWin records derived from satellite measures are in better agreement with in situ observations than estimated SWin and LWin records parametrized from observations performed at the closest off-glacier station. Moreover, we find that the former estimated records permit a significantly better quantification of glacier melting than the latter estimated ones.

The Association between the Frequency of Rhegmatogenous Retinal Detachment and Atmospheric Temperature

Rhegmatogenous retinal detachment (RRD) frequency was observed to be higher with an increase in the daily temperature range. This showed that a wide daily range of temperature, rather than the absolute value of the temperature, is associated with the occurrence of RRD. Purpose. To investigate the association between the frequency of rhegmatogenous retinal detachment (RRD) and the atmospheric temperature. Method. A retrospective review of consecutive eyes that had undergone primary RRD surgery from 1996 to 2016 at Chungbuk National University Hospital was conducted. Temperature data (highest, lowest, and mean daily temperatures and daily temperature range) in Chungbuk Province were obtained from the Korean Meteorological Administration database. We investigated the relationship between the daily temperature range and the frequency of RRD surgery. We also analyzed the association between various temperature data and the frequency of RRD surgery. Result. There were 1,394 RRD surgeries from 1996 to 2016. Among them, 974 eyes were included in this study. The monthly average number of RRD operations showed a bimodal peak (in April and October) throughout the year. With the same tendency as the frequency of RRD, the monthly average of the daily temperature range over 1 year also showed a bimodal peak in April and October. There was a significant positive correlation between the monthly average of the daily temperature range and the number of RRD surgeries (r = 0.297, P<0.001). However, there were no associations between RRD frequency and the mean temperature, highest temperature, and lowest temperature. Conclusion. The higher the daily temperature range, the higher was the RRD frequency observed. We speculated that dynamic changes in temperature during the day may affect degrees in chorioretinal adhesion and liquefaction of the vitreous, which may eventually result in retinal detachment. Therefore, further experimental studies on the correlation between temperature changes and retinal detachment are needed.

Effect of meteorological factors and air pollutants on out-of-hospital cardiac arrests: a time series analysis

ObjectivesWe aimed to investigate the effects of meteorological factors and air pollutants on out-of-hospital cardiac arrest (OHCA) according to seasonal variations because the roles of these factors remain controversial to date.MethodsA total of 38 928 OHCAs of cardiac origin that occurred within eight metropolitan areas between 2012 and 2016 were identified from the Korean nationwide emergency medical service database. A time series multilevel approach based on Poisson analysis following a Granger causality test was used to analyse the influence of air pollution and 13 meteorological variables on OHCA occurrence.ResultsParticulate matter (PM) ≤2.5 µm (PM2.5), average temperature, daily temperature range and humidity were significantly associated with a higher daily OHCA risk (PM2.5: 1.59%; 95% CI: 1.51% to 1.66% per 10µg/m3, average temperature 0.73%, 95% CI: 0.63% to 0.84% per 1°C, daily temperature range: 1.05%, 95% CI: 0.63% to 1.48% per 1°C, humidity −0.48, 95% CI: −0.40 to −0.56 per 1%) on lag day 1. In terms of the impact of these four risk factors in different seasons, average temperature and daily temperature range were highly associated with OHCA in the summer and winter, respectively. However, only PM2.5 elevation (to varying extents) was an independent and consistent OHCA risk factor irrespective of the season.ConclusionsPM2.5, average temperature, daily temperature range and humidity were independently associated with OHCA occurrence in a season-dependent manner. Importantly, PM2.5 was the only independent risk factor for OHCA occurrence irrespective of seasonal changes.

Projected changes of temperature extremes over Southeast Asia under 1.5 and 2 degrees global warming

&lt;p&gt;Projected changes in temperature extremes at 1.5&amp;#176;C and 2&amp;#176;C global warming levels (GWLs) have been evaluated for Southeast Asia (SEA) based on temperature extreme indices from ETCCDI using the latest available CORDEX simulations. Results show that the temperature indices significant increase across Indochina Peninsula and Maritime Continent at 1.5&amp;#176;C and 2&amp;#176;C GWLs except for the decreasing daily temperature range (DTR) in the dry season. The most pronounced increases of summer days (SU) are projected in Sulawesi with the percentage magnitude of 31.7% and 19.7% (47.2% and 31.3%) at the 1.5&amp;#176;C (2&amp;#176;C) GWL for wet and dry seasons, respectively, while tropical nights (TR) increase significantly over Sumatra and Sulawesi. Robust differences of temperature extremes can be found over the SEA in both wet and dry seasons for the additional global warming of 0.5&amp;#176;C. The temperature extremes under the global warming of 1.5&amp;#176;C and 2&amp;#176;C levels and their differences primarily concentrate on the main islands in the densely populated coastal regions, suggesting more conspicuous impacts on the human system in the developing countries over the SEA.&lt;/p&gt;