The National Oceanic and Atmospheric Administration’s Storm Prediction Center (NOAA SPC) provides one- to eight-day severe weather forecast for the U.S. that includes tornado watch. To extend the current severe weather forecast beyond eight days to 2 - 4 weeks (i.e., subseasonal time scale), many studies have looked into the Madden-Julian Oscillation (MJO), a patch... Continue Reading →
Spatiotemporal diversity of Atlantic Niño and associated rainfall variability over West Africa and South America
A phenomenon known as Atlantic Niño is characterized by the appearance of warm sea surface temperature anomalies (SSTAs) in the eastern equatorial Atlantic in northern summer. When it attains its full strength, it increases rainfall and the frequency of extreme flooding over the West African countries bordering the Gulf of Guinea and in northeastern South... Continue Reading →
Pantropical response to global warming and the emergence of a La Nina-like mean state trend
During the past century, the tropical Pacific Ocean has warmed significantly less than the other tropical oceans in response to increasing greenhouse gases (GHGs). This La Nina-like warming trend in the observations is in stark contrast to the El Nino-like warming trend projected by the Coupled Model Intercomparison Project (CMIP) models for both the 20th... Continue Reading →
North Atlantic Ocean gyre circulation dictates the interannual sea level variability along the U.S. Southeast and Gulf Coasts
Interannual and longer time-scale sea level changes are relatively small amplitude. However, they can provide background conditions favorable for the occurrence of extreme sea levels that represent a threat for coastal communities, especially in low-lying and flood-vulnerable regions. A new study accepted in Geophysical Research Letters identified the dominant mode of the ocean gyre-scale sea surface height... Continue Reading →
Extreme U.S. Great Plains heat waves are linked to East Asian Monsoon
Heat waves are the leading weather‐related cause of death in the U.S. For example, the most recent U.S. extreme heat waves that occurred over the Great Plains in 2011 and 2012 caused 362 deaths. These events are unusual and largely unpredictable beyond the synoptic time scale. However, their number and severity have increased and are projected... Continue Reading →
Co-variability of salinity, nutrients and coastal currents in the northern Gulf of Mexico and its impact on plankton biomass
The northern Gulf of Mexico (GoM) is a region strongly influenced by river discharges of freshwater and nutrients, which promote a highly productive coastal ecosystem that host commercially valuable marine species. A new study appeared in Scientific Report utilized a regional ocean-biogeochemical model and observations to show that El Niño - Southern Oscillation (ENSO) is a main... Continue Reading →
Global meridional overturning circulation revisited
Ocean tracers such as heat, salt and carbon are perpetually carried by the global meridional overturning circulation (GMOC) and redistributed between hemispheres and across ocean basins from their source regions. The GMOC is therefore a crucial component of the global heat, salt and carbon balances. In a new article accepted in Geophysical Research Letter, a... Continue Reading →
Influence of global warming on U.S. heat waves may be felt first in the West and Great Lakes regions
Climate projections for the twenty-first century suggest an increase in the occurrence of heat waves. However, the time at which externally forced signals of anthropogenic climate change (ACC) emerge against background natural variability (time of emergence (ToE)) has been challenging to quantify, which makes future heat-wave projections uncertain. Here we combine observations and model simulations... Continue Reading →
On the fragile relationship between El Niño and California rainfall
This study newly accepted in Geophysical Research Letters examined why California experienced extremely wet winter and spring conditions during the 1997-98 and 1982-83 El Niños, but near normal rainfall during the extremely strong 2015-16 El Niño. Statistical data analyses and simple model experiments were used to show that sufficiently warm and persistent sea surface temperature anomalies... Continue Reading →
Pacific origin of the abrupt increase in Indian Ocean heat content during the warming hiatus
Global mean surface warming has stalled since the end of the 20th century, but the net radiation imbalance at the top of the atmosphere continues to suggest an increasingly warming planet. This apparent contradiction has been reconciled by an anomalous heat flux into the Pacific Ocean, induced by a shift toward a La Nina-like state... Continue Reading →