Which of These Was One of the Common Characteristics of the Art Heat 2 Kg of Water From 0 C to 100 C

This indicator describes trends in multi-day extreme heat events across the United States.

• Figure 1. Heat Wave Characteristics in the U.s.a. by Decade, 1961–2019

  This effigy shows changes in the number of heat waves per year (frequency); the average length of estrus waves in days (elapsing); the number of days between the start and last heat moving ridge of the twelvemonth (season length); and how hot the heat waves were, compared with the local temperature threshold for defining a heat moving ridge (intensity). These data were analyzed from 1961 to 2019 for l big metropolitan areas. The graphs testify averages across all 50 metropolitan areas by decade.

  Data source: NOAA, 2021⁷
  Spider web update: April 2021

• Figure 2. Rut Moving ridge Characteristics in 50 Large U.S. Cities, 1961–2019

  These maps show changes in the number of rut waves per yr (frequency); the average length of rut waves in days (duration); the number of days between the first and final heat wave of the yr (flavour length); and how hot the heat waves were, compared with the local temperature threshold for defining a estrus wave (intensity). These data were analyzed from 1961 to 2019 for 50 large metropolitan areas. The size of each circle indicates the total change over the period measured. Solid-color circles represent cities where the tendency was statistically significant.

  Data source: NOAA, 2021^eight
  Web update: April 2021

• Figure 3. U.S. Annual Estrus Wave Index, 1895–2020

  

  This figure shows the annual values of the U.S. Heat Wave Alphabetize from 1895 to 2020. These data cover the contiguous 48 states. An index value of 0.2 (for case) could hateful that 20 percent of the country experienced one heat wave, x percent of the country experienced two heat waves, or some other combination of frequency and area resulted in this value.

  Data source: Kunkel, 2021^nine
  Web update: April 2021

Central Points

• Heat waves are occurring more often than they used to in major cities across the Us. Their frequency has increased steadily, from an average of two rut waves per year during the 1960s to six per year during the 2010s (see Figure i).
•  In recent years, the average estrus wave in major U.Due south. urban areas has been virtually four days long. This is about a day longer than the boilerplate heat wave in the 1960s (see Figure one).
• The average heat wave season beyond the 50 cities in this indicator is 47 days longer now than it was in the 1960s (see Figure 1). Oestrus waves that occur earlier in the spring or afterwards in the fall tin can grab people off-guard and increase exposure to the health risks associated with heat waves.
• Heat waves have get more intense over time. During the 1960s, the boilerplate oestrus wave beyond the 50 cities in Figures ane and 2 was ii.0°F in a higher place the local 85^thursday percentile threshold. During the 2010s, the average heat wave has been ii.5°F above the local threshold (see Effigy 1).
• Of the 50 metropolitan areas in this indicator, 46 experienced a statistically significant increase in heat wave frequency between the 1960s and 2010s. Heat wave duration has increased significantly in 26 of these locations, the length of the heat wave season in 44, and intensity in 16 (see Figure 2).
• Longer-term records prove that heat waves in the 1930s remain the almost severe in recorded U.South. history (see Figure iii). The spike in Figure three reflects extreme, persistent heat waves in the Great Plains region during a period known as the "Dust Bowl." Poor land use practices and many years of intense drought contributed to these heat waves by depleting soil moisture and reducing the moderating effects of evaporation.^{half dozen}

Groundwork

A serial of unusually hot days is referred to equally an extreme rut event or a heat wave. Heat waves are more than than but uncomfortable: they tin can lead to illness and death, particularly among older adults, the very immature, and other vulnerable populations (see the Oestrus-Related Deaths and Heat-Related Illnesses indicators).ⁱ Prolonged exposure to excessive heat can lead to other impacts too—for case, damaging crops, injuring or killing livestock, and increasing the risk of wildfires. Prolonged periods of farthermost heat can lead to power outages as heavy demands for air conditioning strain the power grid.

Unusually hot days and multi-day heat waves are a natural role of day-to-day variation in weather condition. As the Earth's climate warms, however, hotter-than-usual days and nights are becoming more common (see the Loftier and Depression Temperatures indicator) and heat waves are expected to become more frequent and intense.² Increases in these extreme rut events can atomic number 82 to more heat-related illnesses and deaths, specially if people and communities practise not take steps to accommodate.³ Even small increases in extreme oestrus can result in increased deaths and illnesses.^four

About the Indicator

This indicator examines trends over fourth dimension in 4 cardinal characteristics of heat waves in the U.s.:

• Frequency: the number of heat waves that occur every year.
• Duration: the length of each individual estrus wave, in days.
• Season length: the number of days between the first heat wave of the year and the last.
• Intensity: how hot it is during the estrus moving ridge.

Rut waves can be defined in many dissimilar means. For consistency across the country, Figures ane and 2 ascertain a heat wave as a period of two or more sequent days when the daily minimum apparent temperature (the bodily temperature adapted for humidity) in a particular urban center exceeds the 85^th percentile of historical July and August temperatures (1981–2010) for that urban center. This definition is useful for several reasons:

• The most serious health impacts of a heat moving ridge are often associated with high temperatures at dark, which is usually the daily minimum.⁵ The human trunk needs to cool off at night, especially after a hot day. If the air stays too warm at dark, the body faces extra strain as the heart pumps harder to try to regulate torso temperature.
• Adjusting for humidity is of import because when humidity is high, water does not evaporate as easily, so it is harder for the human being body to cool off by sweating. That is why health warnings about extreme estrus are oft based on the "estrus alphabetize," which combines temperature and humidity.
• The 85^th percentile of July and August temperatures equates to the nine hottest days in a typical summertime. A temperature that is typically only recorded nine times during the hottest office of the year is rare plenty that about people would consider it to be unusually hot.
• By using the 85^th percentile for each individual city, Figures 1 and 2 define "unusual" in terms of local weather. After all, a specific temperature like 95°F might be unusually hot in ane city merely perfectly normal in another. Plus, people in relatively warm regions (such as the Southwest) may be better acclimated and adapted to hot weather.

The National Oceanic and Atmospheric Assistants (NOAA) calculated apparent temperature for this indicator based on temperature and humidity measurements from long-term weather stations, which are generally located at airports. Figures 1 and 2 focus on the 50 most populous U.S. metropolitan areas that take recorded weather information from a consistent location without many missing days over the fourth dimension period examined. The year 1961 was chosen as the starting point because most major cities accept collected consistent data since at least that fourth dimension.

Figure 3 provides another perspective to gauge the size and frequency of prolonged heat moving ridge events. It shows the U.S. Annual Heat Moving ridge Alphabetize, which tracks the occurrence of estrus wave conditions beyond the face-to-face 48 states from 1895 to 2020. This alphabetize defines a heat wave equally a catamenia lasting at least four days with an boilerplate temperature that would only be expected to occur one time every 10 years, based on the historical record. The index value for a given year depends on how oftentimes such severe rut waves occur and how widespread they are.

About the Data

Indicator Notes

As cities develop, vegetation is oft lost, and more than surfaces are paved or covered with buildings. This type of evolution tin lead to higher temperatures—office of an effect called an "urban rut island." Compared with surrounding rural areas, built-upwardly areas have higher temperatures, especially at night.^x Urban growth since 1961 may take contributed to part of the increment in heat waves that Figures i and two testify for certain cities. This indicator does non attempt to adjust for the effects of development in metropolitan areas, considering information technology focuses on the temperatures to which people are actually exposed, regardless of whether the trends reverberate a combination of climate change and other factors.

Figures ane and 2 focus on the fifty most populous metropolitan areas that had consummate data for the entire menstruation from 1961 to 2019. Several large metropolitan areas did not have enough information, such as New York Metropolis, Houston, Minneapolis–St. Paul, and Denver. In some of these cases, the best bachelor long-term weather condition station was relocated sometime between 1961 and 2019—for instance, when a new airport opened.

As noted above, Figures 1 and 2 focus on daily minimum temperatures because of the connection between nighttime cooling (or lack thereof) and human wellness. For reference, EPA'due south technical documentation for this indicator shows the results of a similar analysis based on daily maximum temperatures.

Temperature data are less sure for the early function of the 20^thursday century because fewer stations were operating at that time. In addition, measuring devices and methods take changed over time, and some stations have moved. The data in Figure three have been adjusted to the extent possible to account for some of these influences and biases, nonetheless, and these uncertainties are not sufficient to modify the key nature of the trends.

Information Sources

Figures i and two are adapted from an analysis past Habeeb et al. (2015).¹¹ They are based on temperature and humidity measurements from weather condition stations managed by NOAA's National Conditions Service. NOAA calculated daily credible temperatures for metropolitan areas and published the results at: world wide web.ncdc.noaa.gov/societal-impacts/oestrus-stress/information. Effigy 3 is based on measurements from atmospheric condition stations in the National Weather Service Cooperative Observer Network. The data are available online at: www.ncdc.noaa.gov. Components of this indicator tin as well be found at: world wide web.globalchange.gov/indicators.

Technical Documentation

• Download related technical information PDF

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References

^aneSarofim, M.C., Southward. Saha, M.D. Hawkins, D.Thou. Mills, J. Hess, R. Horton, P. Kinney, J. Schwartz, and A. St. Juliana. 2016. Chapter 2: Temperature-related death and illness. In: The impacts of climatic change on man health in the United States: A scientific assessment. U.S. Global Alter Enquiry Program. https://health2016.globalchange.gov.

ⁱⁱ USGCRP (U.Southward. Global Change Enquiry Program). 2017. Climate science special report: Fourth National Climate Assessment, volume I. Wuebbles, D.J., D.W. Fahey, M.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.). https://science2017.globalchange.gov. doi:10.7930/J0J964J6..

³ U.South. EPA (U.Southward. Environmental Protection Bureau). 2015. Climate change in the United States: Benefits of global action. EPA 430-R-15-001. www.epa.gov/cira.

⁴ Sarofim, M.C., S. Saha, Yard.D. Hawkins, D.M. Mills, J. Hess, R. Horton, P. Kinney, J. Schwartz, and A. St. Juliana. 2016. Chapter two: Temperature-related death and illness. In: The impacts of climate change on human health in the United States: A scientific assessment. U.S. Global Change Research Programme. https://health2016.globalchange.gov.

⁵ Sarofim, Thousand.C., Due south. Saha, Thou.D. Hawkins, D.Yard. Mills, J. Hess, R. Horton, P. Kinney, J. Schwartz, and A. St. Juliana. 2016. Affiliate 2: Temperature-related expiry and illness. In: The impacts of climatic change on human health in the U.s.a.: A scientific cess. U.S. Global Change Research Program. https://health2016.globalchange.gov.

^six CCSP (U.S. Climatic change Science Programme). 2008. Synthesis and Cess Product three.3: Atmospheric condition and climate extremes in a irresolute climate. www.globalchange.gov/scan/reports/sap-33-weather condition-and-climate-extremes-irresolute-climate.

⁷ NOAA (National Oceanic and Atmospheric Administration). 2021. Heat stress datasets and documentation. Accessed February 2021. www.ncdc.noaa.gov/societal-impacts/heat-stress/data.

⁸ NOAA (National Oceanic and Atmospheric Administration). 2021. Rut stress datasets and documentation. Accessed February 2021. www.ncdc.noaa.gov/societal-impacts/oestrus-stress/data.

^ixKunkel, K. 2021. Updated version of Effigy 2.3 in: CCSP (U.S. Climatic change Science Program). 2008. Synthesis and Cess Production 3.iii: Weather condition and climate extremes in a irresolute climate. www.globalchange.gov/browse/reports/sap-33-weather condition-and-climate-extremes-irresolute-climate​.

¹⁰ U.S. EPA (U.South. Environmental Protection Agency). 2016. Heat island effect. www.epa.gov/heatislands.

¹¹ Habeeb, D., J. Vargo, and B. Stone, Jr. 2015. Rising heat wave trends in large U.Due south. cities. Nat. Hazards 76(3):1651–1665. doi:10.1007/s11069-014-1563-z.

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Source: https://www.epa.gov/climate-indicators/climate-change-indicators-heat-waves

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