Center for Climate Sciences

The influenza, or flu, virus infects millions of people in the United States each year, mostly during winter. To help limit the impacts of seasonal flu outbreaks, scientists have been trying to anticipate when the outbreaks occur using a variety of information.

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The influenza, or flu, virus infects millions of people in the United States each year, mostly during winter. To help limit the impacts of seasonal flu outbreaks, scientists have been trying to anticipate when the outbreaks occur using a variety of information. Laboratory studies have pointed to humidity playing an important role in the transmission of flu. The average amount of water vapor in the air we breathe varies widely across the U.S., but even in the most humid areas, it begins to drop as winter approaches.

Researchers at NASA’s Jet Propulsion Laboratory and the University of Southern California have used NASA satellite data from the Atmospheric Infrared Sounder (AIRS) to illuminate the relationship between low humidity and the outbreak of flu in the U.S. They compared AIRS measurements of water vapor in the lower atmosphere with flu case estimates over a twelve year period. For each state, they identified specific levels of low humidity that signal the start of a flu outbreak. These threshold levels of low humidity vary between the states but follow regional patterns and are tied to each state’s average climate. States with humid climates, such as those in the Southeast, have higher threshold values than arid states, including those in the West and Southwest.

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When designing a space mission, there are many parameters to take into account. There are often trade-offs between different design parameters.

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When designing a space mission, there are many parameters to take into account. For instance, a space-borne instrument will observe a swath of the Earth’s surface as it orbits, and the width of that swath depends on the instrument itself, as well as high above the Earth it flies. There are also often trade-offs between different design parameters. For example, the same instrument can be used in a mission that acquires very fine features on the surface infrequently, or it can focus on larger features but visit them more often. It can be difficult to optimize these design decisions for missions that produce many products in different science focus areas (e.g. the design best for studying water is probably not the same as the design best for land).

NASA’s Earth System Observatory will include a mission to map Earth’s Surface Biology and Geology. The mission will monitor volcanic eruptions, snow-melt, water quality, vegetation health, and more. Each of these areas prioritize different instrument parameters. This study proposed a new metric by which to optimize mission design parameters: intrinsic dimensionality. This is a mathematical metric independent of application area, and can be used to design a mission that provides the best compromise between the needs of different areas.

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Heat stress is a rapidly increasing threat to human health and energy demand across the US and the globe. Both high temperatures and high moisture levels are important contributors to heat stress, and it is well-known that future temperature increases will generally be larger in mountains due to there being much less snow and drier soils.

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Heat stress is a rapidly increasing threat to human health and energy demand across the US and the globe. Both high temperatures and high moisture levels are important contributors to heat stress, and it is well-known that future temperature increases will generally be larger in mountains due to there being much less snow and drier soils. But with moisture increasing rapidly at low elevations, which factor will dominate the total response?

Scientists at JPL and several other institutions looked at all available high-resolution climate-model data and found that the temperature effect best explains the total change in heat stress. However, the more humid a climate zone, the more moisture matters in explaining the magnitude of the changes. These findings help understand where and why heat stress is likely to increase most dramatically, and motivate efforts to make investments and other preparations in the areas of greatest change, such as the southern Appalachians and southern Rocky Mountains.

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Sequences of extreme climate events, or multiple ones occurring simultaneously, can have impacts that are ‘larger than the sum of their parts’.

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Sequences of extreme climate events, or multiple ones occurring simultaneously, can have impacts that are ‘larger than the sum of their parts’. For example, bad harvests in several major crop-growing areas can lead to shortages, price shocks, and malnutrition, while oscillations between wet and dry years create larger wildfire risks than dry years alone, by increasing the quantity of vegetation available for burning. Using many versions of the same climate model to represent these events increases the confidence with which scientists can draw conclusions about them.

JPL scientists and colleagues looked at 100 end-of-century climate-model outputs for specific sets of conditions that have been linked to impacts on, for example, food security and wildfire risk. The heat-and-drought levels that historically cause bad harvests will occur simultaneously in the six major corn-growing areas about every 4 years, versus every 18 years now. The chance of a very wet year followed by a very dry year will increase by about 25% in California and many other wildfire-prone areas. Such multi-part interactions are critical to take into account for societal resilience in a warming climate.

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In the first year of the COVID-19 pandemic, measures enacted by local, state, and national governments to slow the spread of the virus also caused reductions in some human activities, such as traffic. This, in turn, led to lower emissions of greenhouse gases and air pollutants in a very short time period.

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In the first year of the COVID-19 pandemic, measures enacted by local, state, and national governments to slow the spread of the virus also caused reductions in some human activities, such as traffic. This, in turn, led to lower emissions of greenhouse gases and air pollutants in a very short time period. Changes in emissions that would normally take years or decades occurred over a few weeks, which gave a novel view into the relationship between human activities and atmospheric composition.

The Keck Institute for Space Studies launched a workshop to study these pandemic-induced changes. The results highlighted important ways climate and air quality are linked, such as reduced air pollutant emissions increasing the lifetime of methane in the atmosphere, or wildfires in the western US, which are worsening in response to climate change, causing poor air quality despite the reduction in traffic emissions. A key message was that it is becoming increasingly important to treat air quality and greenhouse gases as truly intertwined challenges.

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As our climate changes, droughts are becoming more frequent, with more than 20% of land in the Western US currently experiencing extreme or exceptional drought.

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As our climate changes, droughts are becoming more frequent, with more than 20% of land in the Western US currently experiencing extreme or exceptional drought. Monitoring these droughts is important for farmers, resource managers, and other leaders to allocate resources to the hardest-hit regions. It is also important for scientists to understand the way that different plants respond to heat and drought, in order to predict how ecosystems may behave in the future.

Scientists at the NASA Jet Propulsion Laboratory (JPL) and the United States Department of Agriculture (USDA) have collaborated to produce a data product derived from ECOSTRESS, a thermal instrument on the International Space Station (ISS). This measure of plant stress is called evapotranspiration and is now available to the general public. The remote sensing product has been shown to be highly representative of ground conditions.

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NOx is a family of air pollutants that are a key factor controlling amounts of both ozone and particulate matter (PM) in the air. Reducing NOx emissions has been an important strategy for improving air quality in the US for decades.

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NOx is a family of air pollutants that are a key factor controlling amounts of both ozone and particulate matter (PM) in the air. Reducing NOx emissions has been an important strategy for improving air quality in the US for decades. But emissions are only one half of the equation setting the amount of NOx in our cities’ air – its lifetime, or how long it stays in the air, is equally important.

Observation of NOx from space provide a unique insight into NOx lifetime. How quickly NOx concentrations decrease downwind of a source (such as a city) can be seen from space, and that rate of decrease gives a good measure of NOx lifetime. Scientists from UC Berkeley used NASA data to track how NOx lifetime changed in almost 50 cities across North America. They found that changes in lifetime help explain why NOx concentrations in the US haven’t been decreasing after 2010, despite evidence that emissions have continued to decrease.

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