Articles

A massive plume of sand and dust was pushed northward from the Sahara desert by the calima, a warm southeasterly wind prevalent in North Africa in the winter, as seen in a satellite view of Spain and Portugal. Image: February 21, 2016, NASA.

Deep Space Mapping of Saharan Dust Height

Caitlin Dempsey

Researchers used four years of measurements from a deep space satellite to calculate the average monthly heights of Saharan dust clouds.

Map showing the NDVI anomaly in 2024 compared to average levels from 1991 to 2020). After a couple of years of above average precipitation in Southern California, vegetations levels in the summer of 2024 were 30% greener than average. Map: NASA, public domain.

Hydroclimate Whiplash: the Impact on California Wildfires

Caitlin Dempsey

Rapid shifts between extremely dry and unusually wet conditions are reshaping Californiaโ€™s fire landscape by increasing vegetation growth, drying fuels, and contributing to more intense wildfires.

A photo taken from space that has been labeled with place names of an open water estuary.

Florida’s Largest Open Water Estuary

Caitlin Dempsey

Covering an area of about 400 square miles, Tampa Bay is Florida's largest open water estuary.

A Tweet from 2020 comparing a map to an animal.

Cartopareidolia: Seeing People and Animals in Maps

Caitlin Dempsey

Cartopareidolia is the tendency to see familiar shapes, animals, faces, and objects in coastlines, borders, and maps.

A screenshot of an application showing a basemap of the SF bay area with blue lifework on top of it.

Shapefile Viewers

Caitlin Dempsey

Explore viewers for visualizing GIS vector data in shapefile format, available for both desktop and web browsers.

Sado Island: An Example of Tripartite Geography

Caitlin Dempsey

Sado Island is an example of a landmass with tripartite physical geography.

Visualization by NASA showing the retreat of the Smith Glacier grounding line between 1996 and 2011.

Understanding Glacier Grounding Lines

Caitlin Dempsey

Grounding lines are the boundaries where glaciers and ice sheets transition from resting on solid ground to floating on seawater.

With pansharpening, the panchromatic Landsat spectral band can be used to increase the resolution of Landsat imagery.

Pan Sharpen Landsat Imagery in QGIS

Caitlin Dempsey

This QGIS tutorial guides you through pan sharpening Landsat imagery by combining the 15-meter panchromatic band with lower-resolution multispectral bands.

A pan sharpened Landsat 8 satellite image of Mount Jefferson in Oregon on the right with the unsharpened natural color image on the left. Images: NASA, public domain,

Pan Sharpening in GIS

Caitlin Dempsey

Enhance spatial detail in multispectral images with pan sharpening. Learn how this GIS technique combines data for sharper, more detailed satellite imagery.

A satellite image of islands.

Isostatic Rebound: How Earth’s Surface Rises after Glaciers Retreat

Caitlin Dempsey

Isostatic rebound is the Earth's slow rise after glaciers melt, reshaping coastlines, revealing landforms, and altering sea levels globally.

A satellite image of a cavum.

Cavum: Hole-punch Clouds

Caitlin Dempsey

Cavums are also known as hole-punch clouds or fallstreak holes.

A black and a brown cow in a grassy pasture.

Mapping Methane: the Launch of MethaneSAT and the Limitations of Satellite Data

Caitlin Dempsey

While advances in remote sensing and satellite technology have improved methane mapping, ground measurements remain essential for accurate, localized data.

Map showing areas of increased artificial lighting in the Arctic, with increases in yellow, decreases in purple, and no change in green, using data from the U.S. DMSP satellites. Map: NASA, public domain.

Increased Light Pollution in the Arctic

Caitlin Dempsey

Satellite data reveals growing nighttime light levels across the Arctic, linked to expanding oil, gas, shipping, and infrastructure activity.

This 2024 Landsat 8 image shows Yakutat, Alsek, and Grand Plateau Glaciers have retreated up to 7.8 kilometers (4.8 miles), with lakes filling the void. Over 40 years, the lakes more than doubled in size to 240 square kilometersโ€”larger than New Yorkโ€™s Seneca Lake.

The Rise of Proglacial Lakes

Caitlin Dempsey

Glacial retreat in Alaska's Yakutat Foreland has fueled rapid growth of proglacial lakes, doubling their size in 40 years as seen in Landsat imagery.

Earthrise over the Moon: partly-illuminated Earth rising over the lunar horizon. In this photo, the Earth is about 400,000 miles away. Photo: Apollo 11, AS11-44-6552, July 20, 1969.

Overview Effect: Quotes from Astronauts After Seeing the Earth from Space

Caitlin Dempsey

The Overview Effect is a shift in awareness by astronauts seeing Earth from outer space as a โ€œtiny, fragile ball of life.โ€

A comma-shaped cloud pattern on a storm seen on a satellite image.

Extratropical Cyclones in the United States

Caitlin Dempsey

Extratropical cyclones are powerful storms forming between 30ยฐโ€“60ยฐ latitude, driven by temperature contrasts.

A photo looking up towards the sky of conifer trees on a blue sunny day.

Land Carbon Storage Declined Sharply in 2023

Caitlin Dempsey

Global land carbon storage saw a significant decline in 2023, driven by extreme droughts, wildfires, and heatwaves.

A satellite image of the wester Pacific Ocean showing four active storms.

Storms in the Western Pacific Ocean

Caitlin Dempsey

The western Pacific experienced a rare event in November 2024 with four simultaneous storms.

A map with gradients of purple to against an off white map of continents in the Arctic.

Planting Trees in the Arctic May Contribute to Climate Change

Caitlin Dempsey

Afforestation in Arctic regions may accelerate permafrost thaw, releasing stored carbon and potentially exacerbating climate change.

Image from NASA's Aqua satellite showing Saharan dust and a phytoplankton bloom (bright blue) off the coasts of France and Spain.

Desert Dust Triggers Photoplankton Blooms in the Ocean

Caitlin Dempsey

Saharan dust carries vital nutrients across oceans, triggering phytoplankton blooms that boost marine productivity and influence global carbon cycles.

Satellite image of a piedmont glacier in Alaska with the different lobes labeled.

Largest Piedmont Glacier in North America

Caitlin Dempsey

Southeastern Alaska is home to North Americaโ€™s largest piedmont glacier, where mountain ice spreads outward across a broad coastal plain.

Collage of three books.

Pushing the Boundaries of Geospatial: New Books from Esri Press

Caitlin Dempsey

Three recent publications from Esri Press: Mapping the Deep, The Geography of Hope, and The Power of Where.

Lenticular clouds over a mountain range.

Lenticular Clouds

Caitlin Dempsey

Lenticular clouds are lens-shaped formations that form over mountains when moist air cools and condenses, creating smooth, often UFO-like cloud patterns.

Taken at about 30,000 feet (9 kilometers) over eastern Washington, the smoke plume (gray) feeds the pyrocumulonimbus cloud (white). Photo: David Peterson (U.S. Naval Research Laboratory), public domain, August 8, 2019.

Understanding the Increase in PyroCbs: Wildfire Thunderstorms

Caitlin Dempsey

Wildfire-driven thunderstorms, known as pyroCbs (pyrocumulonimbus clouds), are becoming more frequent.

Screenshot from an interactive map website showing transit maps.

Automating a London Tube Style Transit Map of the World

Caitlin Dempsey

Using OpenStreetMap data, researchers created an automated world transit map with simplified layouts modeled after the London Tube map design.

A view on a bright sunny day of a street in a residential neighborhood with some trees.

Study: Cities at Higher Latitudes Benefit More from Urban Vegetation Cooling

Caitlin Dempsey

Study in Nature Communications examined cooling benefits of urban vegetation in 468 cities to see where parks and greenery benefit residents most.

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