Studying precipitation patterns

Rain in the Andes, warm winters in Boone – geographers try to piece together a pattern and predict climate change

Appalachian State University geography graduate student Jason Endries is obsessed with precipitation here and in the Andes, where he is capturing and analyzing precipitation data for his master’s degree in geography.

Specifically, he is studying, as a member of Dr. Baker Perry’s research team, precipitation patterns in Peru and Boliva, “trying to gain a better understanding of the processes [so as to] prepare the region for a changing climate and how El Niño and La Niña will impact freshwater resources.”

La Niña is characterized by unusually cold ocean temperatures in the eastern Equatorial Pacific, compared to El Niño, which is characterized by unusually warm ocean temperatures in the eastern Equatorial Pacific.

According to Endries and Perry, the outlook does not look good: Ice caps and glaciers, which ultimately dictate streamflow during the dry season, depend on frozen precipitation for their survival. Rain is falling on the glacier surfaces ¬– Appalachian research instruments have confirmed this, Perry said – and because of the warmer atmosphere, likely a result of climate change and El Niño, precipitation in the form of rain is expected to increase in higher altitudes. Persistent rain will melt snow and ice, increasing rates of deglaciation.

Perry is Endries’ mentor, a respected snow expert who confers regularly with his colleagues in the Northwest Snow Flow group as well as with his researchers on the ground in the Central Andes. Perry is also the graduate program director and an associate professor in the Department of Geography. We asked him about the correlation between his research in the Andes and what Endries termed “weather weirding” around the world.

In Perry’s words, a common theme in his research both in the Andes and in the Appalachians is the importance of changing atmospheric circulation as a component of climate variability and climate change.

In the Andes, the 2015-16 strong El Niño event resulted in above-normal temperatures and significantly more rain falling on glacier surfaces that accelerated the rates of glacier retreat, contributing to extended drought in La Paz, Bolivia, which has led to major water shortages, according to Perry.

As to “weather weirding,” Perry said, in the Appalachians, “El Niño was likely partly responsible for the record warmth in December 2015 and the first part of 2016 and the abysmal start to the ski season that winter. There are signs in both locations that weather is becoming more volatile with increasing precipitation variability, such as floods and drought. The observed anomalous warmth and variability in precipitation in both locations is very likely due to growing human influence on climate,” he said.

Build your snow-cabulary

Endries earned his B.S. in meteorology from the Department of Marine, Earth and Atmospheric Sciences at N.C. State University. Well-versed in all types of precipitation, he has a precise snow-cabulary. He described some of the different types of flakes as:

  • stellar dendrites (tree-like and most widely known)
  • graupel (dense granules that do not contribute as much to accumulation, and the form Perry has great affinity for)
  • needles (like white hairs on your coat sleeve)
  • plates (flat, thin pieces of ice)

He also explained the workings of a multi-angle snowflake camera (MASC) and its value to research.

The MASC allows researchers to take detailed 3-D photos of snow crystals as they fall. With exposure timing as quick as 1/25,000 of a second, the device can also measure the speed the flakes are falling – all without touching them. Classifying the crystals, Endries explained, is valuable in weather modeling, avalanche prediction, impacts on topography and glacial melt. Perry has applied for a grant to purchase a MASC for the Department of Geography and Planning.

According to Perry, had Appalachian had access to an MASC during the winter storm Jan. 6-7, 2017, which blanketed much of the region, his research team would have gathered detailed photos of the snow crystals all through the night. The photographs could have provided a dataset to analyze the type of crystals and degree of riming – coating of tiny, white, granular ice particles, caused by the rapid freezing of super-cooled water droplets on impact with an object – in the numerical forecast models.

“Real-time observations would have also allowed meteorologists at the National Weather Service to see the type of crystals falling and allow them to update snowfall forecasts based on interpretations of the cloud microphysical environment and new snow density associated with the different crystals,” he said.

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