An Evaluation of Problems Affecting the Measurement of Low Relative Humidity on the United States Radiosonde

1994 ◽  
Vol 11 (3) ◽  
pp. 687-700 ◽  
Author(s):  
Charles G. Wade
Keyword(s):  
United States ◽  
Relative Humidity ◽  
The United States

scholarly journals Effects of trees, gardens, and nature trails on heat index and child health: design and methods of the Green Schoolyards Project

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kevin Lanza ◽  
Melody Alcazar ◽  
Deanna M. Hoelscher ◽  
Harold W. Kohl
Keyword(s):  
Physical Activity ◽  
United States ◽  
Relative Humidity ◽  
Air Temperature ◽  
The United States ◽  
Heat Index ◽  
Activity Levels ◽  
Natural Setting ◽  
Physical Activity Levels ◽  
Nature Trails

Abstract Background Latinx children in the United States are at high risk for nature-deficit disorder, heat-related illness, and physical inactivity. We developed the Green Schoolyards Project to investigate how green features—trees, gardens, and nature trails—in school parks impact heat index (i.e., air temperature and relative humidity) within parks, and physical activity levels and socioemotional well-being of these children. Herein, we present novel methods for a) observing children’s interaction with green features and b) measuring heat index and children’s behaviors in a natural setting, and a selection of baseline results. Methods During two September weeks (high temperature) and one November week (moderate temperature) in 2019, we examined three joint-use elementary school parks in Central Texas, United States, serving predominantly low-income Latinx families. To develop thermal profiles for each park, we installed 10 air temperature/relative humidity sensors per park, selecting sites based on land cover, land use, and even spatial coverage. We measured green features within a geographic information system. In a cross-sectional study, we used an adapted version of System for Observing Play and Recreation in Communities (SOPARC) to assess children’s physical activity levels and interactions with green features. In a cohort study, we equipped 30 3rd and 30 4th grade students per school during recess with accelerometers and Global Positioning System devices, and surveyed these students regarding their connection to nature. Baseline analyses included inverse distance weighting for thermal profiles and summing observed counts of children interacting with trees. Results In September 2019, average daily heat index ranged 2.0 °F among park sites, and maximum daily heat index ranged from 103.4 °F (air temperature = 33.8 °C; relative humidity = 55.2%) under tree canopy to 114.1 °F (air temperature = 37.9 °C; relative humidity = 45.2%) on an unshaded playground. 10.8% more girls and 25.4% more boys interacted with trees in September than in November. Conclusions We found extreme heat conditions at select sites within parks, and children positioning themselves under trees during periods of high heat index. These methods can be used by public health researchers and practitioners to inform the redesign of greenspaces in the face of climate change and health inequities.

An Evaluation of NDFD Weather Forecasts for Wildland Fire Behavior Prediction

2018 ◽  
Vol 33 (1) ◽  
pp. 301-315 ◽  
Author(s):  
Wesley G. Page ◽  
Natalie S. Wagenbrenner ◽  
Bret W. Butler ◽  
Jason M. Forthofer ◽  
Chris Gibson
Keyword(s):  
United States ◽  
Wind Speed ◽  
Relative Humidity ◽  
Air Temperature ◽  
Wildland Fire ◽  
Fire Behavior ◽  
The United States ◽  
Mean Bias Error ◽  
Bias Error ◽  
Behavior Prediction

Abstract Wildland fire managers in the United States currently utilize the gridded forecasts from the National Digital Forecast Database (NDFD) to make fire behavior predictions across complex landscapes during large wildfires. However, little is known about the NDFDs performance in remote locations with complex topography for weather variables important for fire behavior prediction, including air temperature, relative humidity, and wind speed. In this study NDFD forecasts for calendar year 2015 were evaluated in fire-prone locations across the conterminous United States during periods with the potential for active fire spread using the model performance statistics of root-mean-square error (RMSE), mean fractional bias (MFB), and mean bias error (MBE). Results indicated that NDFD forecasts of air temperature and relative humidity performed well with RMSEs of about 2°C and 10%–11%, respectively. However, wind speed was increasingly underpredicted when observed wind speeds exceeded about 4 m s−1, with MFB and MBE values of approximately −15% and −0.5 m s−1, respectively. The importance of accurate wind speed forecasts in terms of fire behavior prediction was confirmed, and the forecast accuracies needed to achieve “good” surface head fire rate-of-spread predictions were estimated as ±20%–30% of the observed wind speed. Weather station location, the specific forecast office, and terrain complexity had the largest impacts on wind speed forecast error, although the relatively low variance explained by the model (~37%) suggests that other variables are likely to be important. Based on these results it is suggested that wildland fire managers should use caution when utilizing the NDFD wind speed forecasts if high wind speed events are anticipated.

scholarly journals Effects of trees, gardens, and nature trails on heat index and child health: Design and methods of the Green Schoolyards Project

2021 ◽  
Author(s):  
Kevin Lanza ◽  
Melody Alcazar ◽  
Deanna M. Hoelscher ◽  
III Harold W. Kohl
Keyword(s):  
Physical Activity ◽  
United States ◽  
Relative Humidity ◽  
Air Temperature ◽  
The United States ◽  
Heat Index ◽  
Activity Levels ◽  
Natural Setting ◽  
Physical Activity Levels ◽  
Nature Trails

Abstract Background: Latinx children in the United States are at high risk for nature-deficit disorder, heat-related illness, and physical inactivity. We developed the Green Schoolyards Project to investigate how green features—trees, gardens, and nature trails—in school parks impact heat index (i.e., air temperature and relative humidity) within parks, and physical activity levels and socioemotional well-being of these children. Herein, we present novel methods for a) observing children’s interaction with green features and b) measuring heat index and children’s behaviors in a natural setting, and a selection of baseline results.Methods: During two September weeks (high temperature) and one November week (moderate temperature) in 2019, we examined three joint-use elementary school parks in Central Texas, United States, serving predominantly low-income Latinx families. To develop thermal profiles for each park, we installed 10 air temperature/relative humidity sensors per park, selecting sites based on land cover, land use, and even spatial coverage. We measured green features within a geographic information system. In a cross-sectional study, we used an adapted version of System for Observing Play and Recreation in Communities (SOPARC) to assess children’s physical activity levels and interactions with green features. In a cohort study, we equipped 30 3rd and 30 4th grade students per school during recess with accelerometers and Global Positioning System devices, and surveyed these students regarding their connection to nature. Baseline analyses included inverse distance weighting for thermal profiles and summing observed counts of children interacting with trees.Results: In September 2019, average daily heat index ranged 2.0°F among park sites, and maximum daily heat index ranged from 103.4°F (air temperature = 33.8°C; relative humidity = 55.2%) under tree canopy to 114.1°F (air temperature = 37.9°C; relative humidity = 45.2%) on an unshaded playground. 10.8% more girls and 25.4% more boys interacted with trees in September than in November.Conclusions: We found extreme heat conditions at select sites within parks, and children positioning themselves under trees during periods of high heat index. These methods can be used by public health researchers and practitioners to inform the redesign of greenspaces in the face of climate change and health inequities.

scholarly journals Refining Ornamental Heat Zone Categories with Evapotranspiration

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 884A-884
Author(s):  
Albert Sutherland* ◽  
Mike Schnelle ◽  
Derek Arndt
Keyword(s):  
United States ◽  
Relative Humidity ◽  
Great Plains ◽  
Air Temperature ◽  
Cold Hardiness ◽  
Reference Evapotranspiration ◽  
The United States ◽  
Ornamental Plant ◽  
Heat Zone ◽  
Oklahoma Mesonet

The American Horticulture Society (AHS) Heat Zone categories have been developed to categorize ornamental plant adaptability to different air temperature climates. These zones, like the Plant Hardiness map showing plant cold hardiness zones within the United States, are primarily north to south zones. Within the Great Plains region of the United States, the AHS Heat Zone categories provide a basic level of plant adaptability to air temperature, but do not account for plant reaction to variations in wind, relative humidity or sunlight. Daily reference evapotranspiration provides a single number that responds to variations in air temperature, wind, relative humidity and sunlight. In Oklahoma, the Oklahoma Mesonet provides a uniform statewide network of weather monitor towers that can be used to accurately calculate both short and tall American Society of Civil Engineers (ASCE) reference evapotranspiration (ref ET) across the entire state. Accumulated daily ref ET values can be used to provide further refinement in categorizing ornamental plant adaptability.

scholarly journals Effects of trees, gardens, and nature trails on heat index and child health: Design and methods of the Green Schoolyards Project

2020 ◽  
Author(s):  
Kevin Lanza ◽  
Melody Alcazar ◽  
Deanna M. Hoelscher ◽  
III Harold W. Kohl
Keyword(s):  
Physical Activity ◽  
United States ◽  
Relative Humidity ◽  
Air Temperature ◽  
The United States ◽  
Heat Index ◽  
Activity Levels ◽  
Natural Setting ◽  
Physical Activity Levels ◽  
Nature Trails

Abstract Background: Latinx children in the United States are at high risk for nature-deficit disorder, heat-related illness, and physical inactivity. We developed the Green Schoolyards Project to investigate how green features—trees, gardens, and nature trails—in school parks impact heat index (i.e., air temperature and relative humidity) within parks, and physical activity levels and socioemotional well-being of these children. Herein, we present novel methods for a) observing children’s interaction with green features and b) measuring heat index and children’s behaviors in a natural setting, and a selection of baseline results.Methods: During two September weeks (high temperature) and one November week (moderate temperature) in 2019, we examined three joint-use elementary school parks in Central Texas, United States, serving predominantly low-income Latinx families. To develop thermal profiles for each park, we installed 10 air temperature/relative humidity sensors per park, selecting sites based on land cover, land use, and even spatial coverage. We measured green features within a geographic information system. In a cross-sectional study, we used an adapted version of System for Observing Play and Recreation in Communities (SOPARC) to assess children’s physical activity levels and interactions with green features. In a cohort study, we equipped 30 3rd and 30 4th grade students per school during recess with accelerometers and Global Positioning System devices, and surveyed these students regarding their connection to nature. Baseline analyses included inverse distance weighting for thermal profiles and summing observed counts of children interacting with trees.Results: In September 2019, average daily heat index ranged 2.0°F among park sites, and maximum daily heat index ranged from 103.4°F (air temperature = 33.8°C; relative humidity = 55.2%) under tree canopy to 114.1°F (air temperature = 37.9°C; relative humidity = 45.2%) on an unshaded playground. 10.8% more girls and 25.4% more boys interacted with trees in September than in November.Conclusions: We found extreme heat conditions at select sites within parks, and children positioning themselves under trees during periods of high heat index. These methods can be used by public health researchers and practitioners to inform the redesign of greenspaces in the face of climate change and health inequities.

scholarly journals Lagged meteorological impacts on COVID-19 incidence among high-risk counties in the United States—a spatiotemporal analysis

2021 ◽  
Author(s):  
Lung-Chang Chien ◽  
L.-W. Antony Chen ◽  
Ro-Ting Lin
Keyword(s):  
United States ◽  
High Risk ◽  
Relative Humidity ◽  
Weather Forecasting ◽  
Spline Interpolation ◽  
The United States ◽  
Meteorological Factor ◽  
Maximum Temperature ◽  
Minimum Relative Humidity ◽  
Spatial Function

Abstract Background The associations between meteorological factors and coronavirus disease 2019 (COVID-19) have been discussed globally; however, because of short study periods, the lack of considering lagged effects, and different study areas, results from the literature were diverse and even contradictory. Objective The primary purpose of this study is to conduct more reliable research to evaluate the lagged meteorological impacts on COVID-19 incidence by considering a relatively long study period and diversified high-risk areas in the United States. Methods This study adopted the distributed lagged nonlinear model with a spatial function to analyze COVID-19 incidence predicted by multiple meteorological measures from March to October of 2020 across 203 high-risk counties in the United States. The estimated spatial function was further smoothed within the entire continental United States by the biharmonic spline interpolation. Results Our findings suggest that the maximum temperature, minimum relative humidity, and precipitation were the best meteorological predictors. Most significantly positive associations were found from 3 to 11 lagged days in lower levels of each selected meteorological factor. In particular, a significantly positive association appeared in minimum relative humidity higher than 88.36% at 5-day lag. The spatial analysis also shows excessive risks in the north-central United States. Significance The research findings can contribute to the implementation of early warning surveillance of COVID-19 by using weather forecasting for up to two weeks in high-risk counties.

scholarly journals Seedborne Cladosporium variabile and Stemphylium botryosum in Spinach

Plant Disease ◽  
2006 ◽  
Vol 90 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Pablo Hernandez-Perez ◽  
Lindsey J. du Toit
Keyword(s):  
United States ◽  
Relative Humidity ◽  
Leaf Spot ◽  
Spinacia Oleracea ◽  
The United States ◽  
Causal Agent ◽  
Similar Species ◽  
Stemphylium Botryosum ◽  
Aerial Hyphae ◽  
Potential Difficulty

Assays of 77 spinach (Spinacia oleracea) seed lots produced in the United States, Denmark, the Netherlands, or New Zealand in 2000 to 2003 showed that Stemphylium botryosum, causal agent of Stemphylium leaf spot, was present in every lot, at a mean incidence of 29.1% per lot. Either Cladosporium variabile, causal agent of Cladosporium leaf spot, or the morphologically similar species C. macrocarpum, was present in 37 of the 77 lots, at a mean incidence of 1.8% per lot. Some seed isolates of S. botryosum and C. variabile proved pathogenic on spinach. Nonpathogenic isolates resembling C. variabile were identified as C. macrocarpum by the absence of torulose aerial hyphae. Pathogenic isolates of S. botryosum were also detected in each of 12 seed lots stored for up to 11 years at 4.4°C and 60% relative humidity. C. variabile or C. macrocarpum was detected in only 2 of the 11 lots, which had been stored for 3 and 8 years. Component seed assays demonstrated that S. botryosum and C. variabile (or C. macrocarpum) were internal and external in spinach seed. S. botryosum was detected in 5 to 76% of the embryos of five seed lots, but the two Cladosporium species were detected in only 0 to 1% of the embryos of these lots. This suggests greater potential difficulty at eradicating S. botryosum than C. variabile from infected spinach seed using seed treatments.

scholarly journals Surface Water Vapor Pressure and Temperature Trends in North America during 1948–2010

2012 ◽  
Vol 25 (10) ◽  
pp. 3599-3609 ◽  
Author(s):  
V. Isaac ◽  
W. A. van Wijngaarden
Keyword(s):  
United States ◽  
Water Vapor ◽  
North America ◽  
Relative Humidity ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
The United States ◽  
Specific Humidity ◽  
Canadian Prairies ◽  
Straight Line

Abstract Over one-quarter billion hourly values of temperature and relative humidity observed at 309 stations located across North America during 1948–2010 were studied. The water vapor pressure was determined and seasonal averages were computed. Data were first examined for inhomogeneities using a statistical test to determine whether the data were fit better to a straight line or a straight line plus an abrupt step, which may arise from changes in instruments and/or procedure. Trends were then found for data not having discontinuities. Statistically significant warming trends affecting the Midwestern United States, Canadian prairies, and the western Arctic are evident in winter and to a lesser extent in spring while statistically significant increases in water vapor pressure occur primarily in summer for some stations in the eastern half of the United States. The temperature (water vapor pressure) trends averaged over all stations were 0.30 (0.07), 0.24 (0.06), 0.13 (0.11), 0.11 (0.07) °C decade−1 (hPa decade−1) in the winter, spring, summer, and autumn seasons, respectively. The averages of these seasonal trends are 0.20°C decade−1 and 0.07 hPa decade−1, which correspond to a specific humidity increase of 0.04 g kg−1 decade−1 and a relative humidity reduction of 0.5% decade−1.

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