Sunday, January 27, 2019

CO2 variations with altitude

In 2011 a new satellite, the ACE (for Atmospheric Chemistry Experiment) revealed that concentration of CO2 trends at 100km altitudes were in the rise over an 8 year period [https://phys.org/news/2012-11-atmospheric-co2-space-junk.html]. Concentrations rose from about 210 to 220 ppm  (see figure below). 

The 2017 paper "Global distribution of CO2 in the upper
troposphere and stratosphere" [https://www.atmos-chem-phys.net/17/3861/2017/acp-17-3861-2017.pdf] presents a profile of the CO2 variations with altitude (see below).
One of the questions I don't have an answer to is whether the relatively high percentages of CO2 at high altitude act to radiate excess heat out into space or just serve as a thicker blanket to keep the warm air concentrated near earth's surface. Whereas CO2 concentrations really don't seem to vary by much in the lower atmosphere (below 12 km or so) the oxygen levels fall dramatically as any climber can tell you (see below). Oxygen levels on the summit of Mount Everest at about 9000 meters are less than 32% at sea level.For CO2 as shown above, their level falls by only 7.5% between elevations of 20 and 35km.

O2 concentrations diminish significantly in the troposphere which extends only to about 11km above the Earth's surface. The thicker blanket of CO2 extends through the troposphere and much of the stratosphere. I am unsure whether this is typical for the atmosphereic distribution of other greenhouse gasses.


Friday, January 25, 2019

Tateyama, Snowfalls and Giant Jellyfish on a Warming Planet


The Tateyama Mountains along the western coast of central Japan have some of the highest snowfalls on the planet. If they do not claim the prize, they are certainly a strong competitor! This is a favorite place for hiking and climbing and it is renowned for its Snow Wall or Yuki-no-Otani. [https://us.jnto.go.jp/ski/archives/126/index.html]. The 500 meter passage lies near the entrance to Murodo station, high in the Japan Alps. The Snow Canyon is overwhelming in scale (below) and serves as an awesome entryway to the Tateyama Caldera.What does this have to do with climate? That is something I'd like to find out more about. My search for annual snowfall totals has not been fruitful.


Beyond this grand gateway you encounter the  summits of Tateyama with Oyama just ahead. This is almost the highest peak in the region [see https://www.alpen-route.com/en/about/highlights/murodo.html for more information about the area]. Oyama is the usual destination for the more adventurous hikers. In the photo below very few of those hikers actually make their way beyond the main path you see in the foreground. The hike quickly becomes a solitary one with spectacular vistas appearing with ones increased elevation. This range of high peaks lies along the rim of a large volcanic caldera believed to have formed about 220,000 years ago [https://matcha-jp.com/en/1969]


The weather underground [https://www.wunderground.com/blog/weatherhistorian/record-snow-depth-for-an-official-site-measured-in-japan.html] notes that the large snowfalls in this area occur due to polar windes blowing across the Japan Sea. The winds pick up moisture from the sea and the rise in elevation encountered cools the wind reducing its capacity to hold moisture which falls as either rain or snow. On my last visit, locals reported that they were expecting to break the record on maximum snow pack. A storm approached the area in late spring but warming temperatures produced rain rather than snow which reduced the total snow pack to under 20meters. 

The Japan Meteorological agency reports that the temperature of the Japan sea has increase by about 1.71 to 1.29C over the last 100 years [https://www.data.jma.go.jp/gmd/kaiyou/english/long_term_sst_japan/sea_surface_temperature_around_japan.html]. As we have learned this increase in temperature will lead to increased atmospheric water vapor. It seems likely that the increased water temperature could result in even heavier future snowfalls in the western Japan Alps. 

The Climate Hot Map site [http://www.climatehotmap.org/global-warming-locations/sea-of-japan.html] reports that anomalous influences of the warming Japan Sea produced an outbreak of giant jelly fish. A 10-ton trawler sank as its crew attempted to haul in their nets which had filled with the giant jelly fish. They are indeed huge reaching 2 meters in diameter and weighing up to 400 pounds (~200kg). 

Other influences on the Japan Sea ecosystem include northward expansion of coral reefs consisting of 5 species found nowhere else in the world. These corals are associated with the world's highest latitude reef systems. Their expansion is reported to be at about 8.7 miles per year or 14km/year.

This warming trend is also likely to push the Kuroshio current (the Pacific equivalent of the Atlantic Gulf Stream) northward bringing with it warmer water and additional ecosystem and climate impacts. 

My guess on possible increased snowfall in the Japan Alps appear unlikely as reported snow totals in Japan appear to be declining [https://backcountrymagazine.com/stories/rising-sun-receding-snow-climate-change-impacting-japans-epic-winters/]. However, the Meteorlogical survey does observe that higher elevations see more snowfall when ambient temps drop below freezing, while lower elevations, without the advantage of colder air, will start to see a spike in rainfall [see https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JD020429]. The figure below from this article shows maximum snow depth variations with elevation. The decrease in maximum snow depth is much greater at lower elevations than at higher. At the elevations of the Tateyama highlands, maximum snow depths may decline, but the reduction will be much greater at lower elevations.

 
Regardless, the Snow Canyon will remain and continue to provide a layered record of annual snow falls in the region.  If you make it to Japan, this is a trip off the beaten path well worth taking.