Boston Startup Says Ocean Salinity May Help Predict Extreme Rain Events

September 12, 2022 by Dan McCue
Boston Startup Says Ocean Salinity May Help Predict Extreme Rain Events
Flooded homes in Kentucky, July 2022. (Source: U.S. Army National Guard)

BOSTON — It is no secret that one of the main features of a changing climate is a dramatic reordering of the global water cycle.

Droughts are becoming more plentiful in places once lush with greenery and epic rain events, like the one recently experienced in Kentucky, are becoming more frequent, more severe and more costly in terms of lost lives and property damage.

Now a Boston startup called Salient is looking to ocean salinity as a tool to help governments, emergency responders, and ordinary citizens respond to growing volatility in the natural world around them.

In a new paper published in the journal Geophysical Research Letters, Salient founder and president Dr. Ray Schmitt says “as the ocean is the ultimate source of all rain, its changing salinities have most clearly revealed the ongoing water cycle intensification.”

He goes on to note that in past research, he and his colleagues at Salient have described how ocean surface salinity variations can predict rainfall on land a season ahead. 

“The idea is simple — if some area of the ocean gets saltier due to increased evaporation, that extra moisture export guarantees that it will rain more somewhere else,” he writes. “Similarly, a fresher than normal ocean indicates less moisture has been exported, so less rain will be available.”

Schmitt says source-sink relationships have been discovered for the U.S. East coast salinities in the spring and Midwest rainfall in the following summer. 

“More recently, we have discovered that additional useful salinity predictors exist for Midwest summer rainfall even further afield,” he writes. “Certain patterns of salinity variations in the Western Tropical Pacific have been shown to significantly improve summer rainfall predictions in the Midwest, particularly for the most intense rain events. 

“While we find that the summer moisture source for the upper Midwest is the Gulf of Mexico, the predictability supplied by the western tropical Pacific salinity pattern is related to tropical rainfall events that both inject latent heat energy into the atmosphere and create salinity anomalies,” he continues. “The injection of energy into the tropical atmosphere can generate standing waves in the jet stream at mid-latitudes that affect the storm track on the continental U.S. 

“That is, while the Gulf of Mexico may be supplying moisture to the north flowing Great Plains Low Level Jet, the pattern of the peaks and troughs of the jet stream is important for sending in the fronts that wring the moisture out in heavy rain events,” he writes.

Though the paper obviously seeks to further Salient’s business as a seasonal and sub-seasonal forecaster, the science and logic behind it is intriguing.

Simply put: Surface salinity is a good indicator of the latent heat energy transfer from the ocean to the atmosphere, and when that energy is released into the tropically moist atmosphere, it sets up “waves” that gather in the mid-latitudes. 

As a result, come summer, fronts tracking along the jet stream path wring the moisture out of the low-level flows carrying moisture northward from the Gulf of Mexico. 

“There is a strong correlation between the tropical salinity features with the number of heavy rainfall days in the Midwest that can lead to the flash flooding observed this summer in Kentucky, Missouri, Illinois and West Virginia,” Schmitt writes, suggesting that grasping the import of such “nuggets of predictability” will be key going forward in anticipating the increasingly volatile weather we are experiencing.

Dan can be reached at [email protected] and at https://twitter.com/DanMcCue.

A+
a-
  • Ocean salinity
  • Ray Schmitt
  • Salient
  • In The News

    Health

    Voting

    Weather

    Storm Carrying Massive 'Gorilla Hail' Hits Parts of Kansas and Missouri

    ST. LOUIS (AP) — Massive chunks of hail pelted parts of Kansas and Missouri on Wednesday night, bringing traffic to... Read More

    ST. LOUIS (AP) — Massive chunks of hail pelted parts of Kansas and Missouri on Wednesday night, bringing traffic to a standstill along Interstate 70, as storms unleashed possible tornadoes and meteorologists urged residents to stay indoors. There were three unconfirmed reports of tornadoes in Wabaunsee... Read More

    More Mountain Snow Expected as Powerful Blizzard Moves Out of Northern California

    TRUCKEE, Calif. (AP) — A powerful blizzard that closed highways and ski resorts had mostly moved through the Sierra Nevada by early... Read More

    TRUCKEE, Calif. (AP) — A powerful blizzard that closed highways and ski resorts had mostly moved through the Sierra Nevada by early Monday but forecasters warned that more snow was on the way for Northern California mountains. Sections of Interstate 80 to the west and north of Lake... Read More

    John Kerry Reflects on Time as Top US Climate Negotiator

    WASHINGTON (AP) — Time was running out and U.S. Climate Envoy John Kerry knew it. International climate talks in mid-December... Read More

    WASHINGTON (AP) — Time was running out and U.S. Climate Envoy John Kerry knew it. International climate talks in mid-December were stuck with no agreement to phase out oil, gas and coal, fossil fuels that are the root cause of global warming. The United Nations sponsored... Read More

    Blizzard Warning of up to 10 Feet of Snow in the Sierra Could Make Travel 'Dangerous to Impossible'

    A Pacific storm packing powerful winds and heavy snow is shaping up to be the strongest of the season, forecasters... Read More

    A Pacific storm packing powerful winds and heavy snow is shaping up to be the strongest of the season, forecasters say, as it pushes toward California with potential blizzard conditions in the Sierra and up to 10 feet (3 meters) of snow in the mountains around Lake Tahoe... Read More

    Wildfire Grows Into Second-Largest in Texas History

    A fast-moving wildfire burning through the Texas Panhandle grew into the second-largest blaze in state history Wednesday, forcing evacuations and... Read More

    A fast-moving wildfire burning through the Texas Panhandle grew into the second-largest blaze in state history Wednesday, forcing evacuations and triggering power outages as firefighters struggled to contain the widening flames. The sprawling blaze was part of a cluster of fires that burned out of control... Read More

    Winter Storm Hits Northeast, Causing Difficult Driving, Closed Schools and Canceled Flights

    HARTFORD, Conn. (AP) — Parts of the Northeast were hit Tuesday by a snowstorm that canceled flights and schools and... Read More

    HARTFORD, Conn. (AP) — Parts of the Northeast were hit Tuesday by a snowstorm that canceled flights and schools and prompted warnings for people to stay off the roads, while some areas that anticipated heavy snow were getting less than that as the weather pattern changed. More... Read More

    News From The Well
    scroll top