Fall Approaches

Fall Colors around Lake Superior, September 23, 2007. Credit: NASA TerraMODIS (Satellite-Sensor)

The autumnal equinox of 2007 occurred at 09:51 UTC on Sunday, September 23, or 05:51 Eastern Time. “Autumnal” instead of “Fall” because:

  1. It’s okay to use for both hemispheres.
  2. Also, you could use this term on any other planets on which you should find yourself.

In northeastern North America, we measure fall by the changes in foliage. And it’s on its way south from Canada.

The calendar may have set September 23 as the first day of autumn in 2007, but the forests that line the eastern shore of Lake Superior had already started to mark the turning of the season. By September 23, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this photo-like image, the forests of northern Michigan and southern Ontario flamed orange as the first trees of the season—maples—began to display their brilliant red and orange fall colors. Veins of green run through the sea of orange where the deciduous forest gives way to deep green pine trees.

The most vivid color is concentrated in Canada’s Ontario Province. Located farther south, Michigan’s trees show only a hint of color. …

The large image provides an unusually cloud-free view of all of the Great Lakes. Similar spots of color stretch across southern Canada and parts of Michigan, Wisconsin, and Minnesota. The northern plains of the United States have started to turn yellow as grasses ripen, but the eastern forests in Pennsylvania and New York remain deep green.

Fall Colors around Lake Superior, NASA Earth Observatory

New York State operates its own fall foliage watch. You can track the progress of the changes on the map provided on their Web site. They were predicting “vibrant, near-peak autumn color” this past weekend for the Adirondacks, the peachy area in northern New York state on the map below.

Here in NYC, we’re still in the green, but I’ve been watching the subtle changes. Individual trees in my neighborhood, including the cherry tree in my backyard, are already picking up shades of yellow and orange.

Vernal equinox and autumnal equinox. These names are direct derivatives of Latin (ver = spring, autumnus = autumn), and as such more apt to be found in writings. Although in principle they are subject to the same problem as the spring/autumn names, their use over the centuries has fixed them to the viewpoint of the northern hemisphere. As such the vernal equinox is the equinox where the Sun passes from south to north [across the equator], and is a zeropoint in some celestial coordinate systems. The name of the other equinox is used less often.
– Wikipedia:Equinox:Names

Links

Wikipedia: Equinox
I Love NY (State) Fall Foliage Report

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Canaries in the Coal Mine: Honeybees and Climate Change

NASA scientist Wayne Esaias believes that a beehive’s seasonal cycle of weight gain and loss is a sensitive indicator of the impact of climate change on flowering plants. A hobbyist beekeeper, he has found signals of climate change in his records of the weight of his beehives, and wants to enlist other beekeepers to contribute their observations as well:

The 25-year NASA veteran has made a career studying patterns of plant growth in the world’s oceans and how they relate to climate and ecosystem change, first from ships, then from aircraft, and finally from satellites. But for the past year, he’s been preoccupied with his bee hives, which started as a family project around 1990 when his son was in the Boy Scouts. According to his honeybees, big changes are underway in Maryland forests. The most important event in the life of flowering plants and their pollinators—flowering itself—is happening much earlier in the year than it used to. – Buzzing About Climate Change

[The] 1-to-5-kilometer-radius area in which a hive’s worker bees forage is the same spatial scale that many ecological and climate models use to predict ecosystems’ responses to climate change. It also matches the spatial scale of satellite images of vegetation collected by NASA’s Terra and Aqua satellites. This similarity of scale means that all these ways of studying ecosystems could be integrated into a more sophisticated picture of how plant and animal communities will respond to climate change than any one method alone could provide. Esaias is particularly interested in comparing the hive data to satellite-based maps of vegetation “greenness,” a scale that remote-sensing scientists commonly use to map the health and density of Earth’s vegetation. Scientists have been making these types of maps for decades, and they have used them to document how warming temperatures in the Northern Hemisphere are causing vegetation to green up earlier in the spring than it did in the 1980s. Such maps are an excellent general indicator of seasonal changes in vegetation, says Esaias, but by themselves, they won’t tell you something as tangible as when plants are flowering. – Will Plants and Pollinators Get Out of Sync?

About half of the approximately 6 million honeybee colonies in the United States are kept by individual or family-scale beekeepers. Esaias’ vision is to develop a how-to guide, an automatic data recorder, and the computer and networking resources at Goddard Space Flight Center that would be needed to collect and preserve the data. Ideally, a hive data recorder would be hooked up to the Internet so that volunteers’ hive weights could appear on a Website hosted at Goddard. His goal is to get the cost per kit below $200 and then to get NASA funding to outfit a network of volunteers — HoneybeeNet — and analyze their data. “Ultimately, what we’d like to have is thousands of these across the country. Even if we can get the cost down to $200 a piece, that is still a lot of money to ask for until you have a test data set that proves it is valuable,” admits Esaias. He’s been working with local bee clubs in Maryland, rounding up some 20 volunteers who already have or are willing to purchase their own scales. He hopes that the data collected during the 2007 spring-summer season will be a prototype that will convince NASA to fund a pilot project.

Links: HoneybeeNetColony Collapse Disorder (CCD)Heat Island Effect

2006 was the fifth-warmest year on record

NASA reports that the five warmest years on record were 2005, 1998, 2002, 2003, and 2006. Put another way, four of the fifth warmest years on record occurred in the last five years. And they expect 2007 to be even warmer than 2006.

The top image is a global map showing temperature anomalies during 2006, blue being the coolest and red being the warmest. Areas with cooler-than-average temperatures appear primarily in the northern Pacific Ocean and Southern Ocean, as well as the interior of Antarctica. The very warmest regions appear in the Arctic and the Antarctic Peninsula, which is consistent with climate predictions that global warming will occur more quickly and dramatically in high latitudes. The red colors that dominate the image reveal the overall warmth of 2006 compared to the long-term average.


The graph below the image tracks mean global temperatures compared to the 1951 to 1980 mean. This graph shows two lines, the 5-year mean, indicated in red, and the annual mean, indicated in pink. Temperatures peaked around 1940 then fell in the 1950s. By the early 1980s, temperatures surpassed those of the 1940s and, despite ups and downs from year to year, they continued rising beyond the year 2000.


– NASA Earth Observatory

News, August 1, 2006: NASA Earth Observatory Maps NYC’s Heat Island, Block by Block

Timely enough, given the record temperatures we’re experiencing this week. Tomorrow’s forecast has been “upgraded” from what I reported yesterday: the THI may reach 117F tomorrow.

Temperatures in New York City as measured by Landsat on August 14, 2002, at 10:30am, during a heat wave. Cooler temperatures are blue, hotter are yellow.
Source: NASA Earth Observatory. Map by Robert Simmon, using data from the Landsat Program.
NASA Map of Surface Temperatures in New York City, 2002-08-14

Temperatures in New York City as measured by Landsat on August 14, 2002, at 10:30am, during a heat wave. Cooler temperatures are blue, hotter are yellow.
Source: NASA Earth Observatory. Map by Robert Simmon, using data from the Landsat Program.
NASA Map of Surface Vegetation in New York City

The ability of vegetation to moderate urban temperatures is graphically demonstrated in these paired images from NASA’s Earth Observatory. The spatial resolution of these images is 60 meters per pixel. At that scale, I can just about make out the block where I garden:

Closeup of the vegetation map, centered on central Brooklyn. The green area at the left is Greenwood Cemetery. Prospect Park is the dark green area at the top; the white area within it is Prospect Lake.

Below the park, to the south, Victorian Flatbush, with its tree-lined streets, detached wood frame houses, and front lawns, spreads out as a series of olive green areas. The beige areas in-between the olive are rowhouses and apartment buildings. You can even make out a curving green line across the southern end of this area: That’s the old LIRR right-of-way, long abandoned, and overgrown with trees.

NASA has just published a report on urban heat islands highlighting the research of Stuart Gaffin, an associate research scientist with the Earth Institute at Columbia University in New York City, and his colleagues:

In the summer of 2002, Gaffin and his colleagues used satellite temperature data, city-wide land cover maps, and weather data, along with a regional climate model to identify the best strategies for cooling the city. The team estimated how much cooling the city could achieve by planting trees, replacing dark surfaces with lighter ones, and installing vegetation-covered “green roofs.”
The team studied the city as a whole, as well as six “hotspot” areas—including parts of Manhattan, the Bronx, Queens, and Brooklyn—where air temperatures near the ground were higher than the city-wide average. Each area was serviced by Con Edison, the local power company, so the scientists could compare electricity use. Each area also had available space so that the mitigation strategies the team considered could be modeled in the study and potentially implemented later on.
August 14 fell on one of the hottest heat wave days in New York’s summer of 2002, making it a good day to take the city’s temperature. Measuring the temperature of every last sidewalk, street, parking lot, roof, garden, and grassy area in an entire city isn’t easily done from the ground, so the researchers relied on NASA to take the city’s temperature from the sky. NASA’s Landsat Enhanced Thematic Mapper collected thermal infrared satellite data. …
Beating the Heat in the World’s Big Cities

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