A view of the aurora borealis from space, captured by the VIIRS instrument aboard the Suomi NPP satellite at 3:20 am CDT on 11 May 2024. NASA Earth Observatory:

The VIIRS day-night band detects nighttime light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as city lights, reflected moonlight, and auroras.

In this view, the northern lights appear as a bright white strip across parts of Montana, Wyoming, the Dakotas, Minnesota, Wisconsin, Iowa, and Michigan. But auroras are dynamic, and different coverage and patterns of light would have been visible at other times of the night. And while these satellite data are shown in grayscale, viewers on the ground saw colors from green (the most common) to purple to red. Atmospheric compounds found at different altitudes influence an aurora’s color.

It boggles the mind a bit that by imaging the aurorae from above, with city lights visible and states and lakes outlined, what we kind of have, above, is a map of the aurorae—at least at a single moment in time.

Devastating floods in Rio Grande do Sul, Brazil’s southernmost state, have killed at least 95 people and displaced 150,000 more. NASA Earth Observatory posted the above Landsat 8 image of downtown Porto Alegre (population: 1.5 million), as well as MODIS images of the overflowing Jacuí River. CNN has before-and-after Maxar imagery of Porto Alegre.

Satellite observations have made it possible to evaluate the success of Ukraine’s wheat and barley harvest, even in active war zones or occupied territories. NASA Earth Observatory reports that the harvest was, in the end, larger than expected: “At the outset of Russia’s full-scale invasion in February, some analysts cautioned that 20 to 30 percent of Ukraine’s winter crops might not be harvested at the end of the summer. However, NASA Harvest’s analysis indicates that 94 percent of the winter crop was harvested, including 88 percent of winter crops in areas not controlled by Ukraine.”

A dust plume from the Sahara, driven by an atmospheric river, blew across western Europe this week, and friends from Spain to Germany experienced it. NASA Earth Observatory has satellite imagery of the plume, plus maps (above) showing “a model of the dust plumes blowing across North Africa and into Europe on March 14 and 15. The model was generated by the Goddard Earth Observing System Model, Version 5 (GEOS-5), a global atmospheric model that uses mathematical equations to represent physical processes. Measurements of physical properties like temperature, moisture, and wind speeds and directions are routinely folded into the model to keep the simulation as close to observed reality as possible.”

NASA Earth Observatory: “The map above shows air temperatures across the United States on September 6, 2020, when much of the Southwest roasted in a dramatic heatwave. The map was derived from the Goddard Earth Observing System (GEOS) model and represents temperatures at 2 meters (about 6.5 feet) above the ground. The darkest red areas are where the model shows temperatures surpassing 113°F (45°C).” Heat waves in southern California have become “more frequent, intense, and longer-lasting,” the article goes on to say.

NASA Earth Observatory has had several stories on the western U.S. wildfires, gathered here. This story summarizes the situation; satellite images of the smoke generated by the fires can be seen here, here and here.

In today's Sunday edition of @washingtonpost pic.twitter.com/qHosujRKrG

— Lauren Tierney (@tierneyl) September 13, 2020

Marena Brinkhurst of Mapbox has a comprehensive list of open data sources relating to the wildfires, smoke, and air quality.

Mark Altaweel at GIS Lounge looks at how GIS is being used to map wildfires, smoke and air pollution.

Previously: California Wildfires, 2020 Edition.

One-third of the United States is currently affected by at least moderate levels of drought, NASA Earth Observatory reports.

The map above shows conditions in the continental U.S. as of August 11, 2020, as reported by the U.S. Drought Monitor program, a partnership of the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and the University of Nebraska—Lincoln. The map depicts drought intensity in progressive shades of orange to red and is based on measurements of climate, soil, and water conditions from more than 350 federal, state, and local observers around the country. NASA provides experimental measurements and models to this drought monitoring effort.

According to the Drought Monitor, more than 93 percent of the land area in Utah, Colorado, Nevada, and New Mexico is in some level of drought; 69 percent of Utah is in severe drought, as is 61 percent of Colorado. More than three-fourths of Oregon, Arizona, and Wyoming are also in drought. The effects of “severe” drought include stunted and browning crops, limited pasture yields, dust storms, reduced well water levels, and an increase in the number and severity of wildfires. Most of those areas had no sign of drought in the mid-summer of 2019.

NASA Earth Observatory maps the bitterly cold temperatures resulting from cold air pushed southwards by an unstable polar vortex. The maps and animations are by Earth Observatory’s lead cartographer, Joshua Stevens. On Twitter he posted a companion visualization showing what’s happening on the other side of the planet, where a searing heat wave is blistering Australia.

Meanwhile on the other side of the planet ?, @NASA ?️ data shows #Australia's daytime temperatures are soaring (≥40 °C) pic.twitter.com/hvBuEez4G6

— Joshua Stevens (@jscarto) January 31, 2019

Landsat observations have charted the erosion of the banks of the ever-changing Padma River, a major distributary of the Ganges in Bangladesh. This is vividly shown in this animation produced by NASA Earth Observatory, which “shows 14 false-color images of the Padma river between 1988 and 2018 taken by the Landsat 5 and 8 satellites. All of the images include a combination of shortwave infrared, near infrared, and visible light to highlight differences between land and water.” More on the erosion of the Padma River here.

NASA Earth Observatory: “The map above depicts changes in water storage on Earth—on the surface, underground, and locked in ice and snow—between 2002 and 2016. Shades of green represent areas where freshwater levels have increased, while browns depict areas where they have been depleted. Data were collected by the GRACE mission, which precisely measured the distance between twin spacecraft as they responded to changes in Earth’s gravity field. In sensing the subtle movements of mass around the planet, the satellites could decipher monthly variations in terrestrial water storage.” The GRACE observations form the basis of a study published this month in Nature on changes in global fresh water availability. More at the JPL’s GRACE-FO project page. [Benjamin Hennig]

NASA Earth Observatory:

Global sea level rise has been accelerating in recent decades, according to a new study based on 25 years of NASA and European satellite data. This acceleration has been driven mainly by increased ice melting in Greenland and Antarctica, and it has the potential to double the total sea level rise projected by 2100[. …]

The rate of sea level rise has risen from about 2.5 millimeters (0.1 inch) per year in the 1990s to about 3.4 millimeters (0.13 inches) per year today. These increases have been measured by satellite altimeters since 1992, including the TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 missions, which have been jointly managed by NASA, France’s Centre national d’etudes spatiales (CNES), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and the U.S. National Oceanic and Atmospheric Administration (NOAA). The maps on this page depict the changes in sea level observed by those satellites between 1992 and 2014.

Cape Town is running out of drinking water, a crisis dramatically depicted by NASA Earth Observatory maps that show the depletion of the city’s reservoirs. The animated gif above, for example, “shows how dramatically Theewaterskloof [Cape Town’s largest reservoir] has been depleted between January 2014 and January 2018. The extent of the reservoir is shown with blue; non-water areas have been masked with gray in order to make it easier to distinguish how the reservoir has changed. Theewaterskloof was near full capacity in 2014. During the preceding year, the weather station at Cape Town airport tallied 682 millimeters (27 inches) of rain (515 mm is normal), making it one of the wettest years in decades. However, rains faltered in 2015, with just 325 mm falling. The next year, with 221 mm, was even worse. In 2017, the station recorded just 157 mm of rain.”

NASA Earth Observatory notes the release of a new map of global landslide susceptibility that models the risks of landslides that are triggered by heavy rain. “The map is part of a broader effort to establish a hazards monitoring system that combines satellite observations of rainfall from the Global Precipitation Measurement (GPM) mission with an assessment of the underlying susceptibility of terrain.” [Geographical]

Meanwhile, NASA Earth Observatory points—while it still can—to a study mapping the extent of existing and potential thermokarst (thawed permafrost) landscapes. On the Earth Observatory maps (see North America, above), “[t]he different colors reflect the types of landscapes—wetlands, lakes, hillslopes, etc.—where thermokarst is likely to be found today and where it is most likely to form in the future.”

Previously: Mapping Arctic Sea Ice; Mapping the Thaw.

NASA Earth Observatory: “In November, the sea ice extent averaged 9.08 million square kilometers (3.52 million square miles)—the lowest November extent in the satellite record. The yellow line shows the median extent from 1981 to 2010, and gives an idea of how conditions this November strayed from the norm.” Also shows sea ice extent for previous years dating back to 1978. Hudson Bay was icebound in November not that long ago.

Previously: Mapping Arctic Sea Ice.