Oceanic response to Hurricane Irma (2017) in the Exclusive Economic Zone of Cuba and the eastern Gulf of Mexico

An understanding of the oceanic response to tropical cyclones is of importance for studies on climate change, ecological variability and environmental protection. Hurricane Irma (2017, Atlantic Ocean) broke many records, including the fact that it was the first category 5 hurricane making landfall in Cuba since 1924. In this study, we assess the oceanic response of the waters of the Cuban Exclusive Economic Zone (EEZ) and the eastern Gulf of Mexico (GoM) to the passage of this hurricane. Overall, Irma led to a weak sea surface cooling in the EEZ, which was associated with the thermal structure of its waters and the fact that it was affected by the left-side quadrants of this hurricane. This cooling was driven by mixing and upwelling processes. In contrast, the chlorophyll-a (chl-a) concentration increase was comparable with climatological records, suggesting that horizontal advection of coastal waters and entrainment of chl-a rich waters from remote regions of the GoM influenced the post-storm chl-a concentration. Moreover, Irma increased the chl-a concentration in the northeastern GoM and stimulated the offshore transport of these chl-a-rich waters to the interior GoM. A high chl-a plume (HCP) extended southward across the eastern GoM during the first post-storm week of Irma, and these waters reached the northwestern Cuban coast following the Loop Current. An intensification of the geostrophic currents of an anticyclonic eddy at the upper front of the Loop Current, the formation of an anticyclonic-cyclonic eddy pair in the northeastern GoM and wind-driven advection governed the extension of this HCP

Tropical Cyclone Future Projections

The increasing frequency of tropical-cyclone damage has attracted public interest regarding the impact of global warming on tropical cyclone activity. Although the global mean temperature has been rising since the 20th century, the detection and attribution of any climate change in tropical cyclone activity remain uncertain due to the limited length of reliable observations. A number of previous studies have reported projected future changes in tropical cyclone frequency. However, there remains substantial uncertainty regarding future changes in tropical cyclone activity and their impact. The publication of this Special Issue aims to minimize uncertainty in the possible future changes in tropical cyclone activity. Individual papers solicited for this Special Issue focus on (1) quantifying change in the characteristics of tropical cyclones in a warmer climate; (2) observed climate change in tropical cyclone activity; (3) assessing tropical cyclone risks, mitigations, and adaptations for future climate change; (4) assessing potential future changes in the impact of tropical cyclones on oceans (e.g., marine biochemistry, marine ecosystem, storm surges, and sea level rise); (5) theoretical or experimental studies related to the tropical cyclone climate

Climate Change Impacts and Projections for the Greater Boston Area: Findings of the Greater Boston Research Advisory Group Report

During the writing of the inaugural Boston Research Advisory Group (BRAG) report both NASA and NOAA announced that 2015 was the warmest year on record, beating the previous record set in 2014, by 0.29 °F. Just five years later (during the writing of this report), NASA announced that 2020 had tied 2016 for the warmest year, breaking the previous record by a stunning 1.84 °F, and that the last seven years have been the warmest seven-year period on record. These observations support the assertion made in the sixth and most recent assessment by the Intergovernmental Panel on Climate Change , which states, “It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.” Hence, the question is not whether the climate is changing, but what we’re going to do about it. At a minimum, we must focus efforts to get to net zero greenhouse gas (GHG) by 2050. It’s not too late to achieve that goal, but time is running out for us to prevent the worst-case scenarios suggested here. This report is broken into four chapters and summarizes the most recent (as of late 2021) scientific understanding of climate risk factors pertinent to Greater Boston

Future behavior of wind wave extremes due to climate change

ABSTRACT: Extreme waves will undergo changes in the future when exposed to different climate change scenarios. These changes are evaluated through the analysis of significant wave height (Hs) return values and are also compared with annual mean Hs projections. Hourly time series are analyzed through a seven-member ensemble of wave climate simulations and changes are estimated in Hs for return periods from 5 to 100 years by the end of the century under RCP4.5 and RCP8.5 scenarios. Despite the underlying uncertainty that characterizes extremes, we obtain robust changes in extreme Hs over more than approximately 25% of the ocean surface. The results obtained conclude that increases cover wider areas and are larger in magnitude than decreases for higher return periods. The Southern Ocean is the region where the most robust increase in extreme Hs is projected, showing local increases of over 2 m regardless the analyzed return period under RCP8.5 scenario. On the contrary, the tropical north Pacific shows the most robust decrease in extreme Hs, with local decreases of over 1.5 m. Relevant divergences are found in several ocean regions between the projected behavior of mean and extreme wave conditions. For example, an increase in Hs return values and a decrease in annual mean Hs is found in the SE Indian, NW Atlantic and NE Pacific. Therefore, an extrapolation of the expected change in mean wave conditions to extremes in regions presenting such divergences should be adopted with caution, since it may lead to misinterpretation when used for the design of marine structures or in the evaluation of coastal flooding and erosion

Tropical Cyclone Intensity and Position Analysis Using Passive Microwave Imager and Sounder Data

Satellite based Tropical Cyclone (TC) intensity estimates are critical for TC warning centers and global Numerical Weather Prediction (NWP) Models due to the lack of in-situ observations of mean sea-level pressure and TC winds. Passive microwave instruments on polar-orbiting weather satellites are useful for estimating the intensity of TCs because upwelling microwave radiation can generally penetrate clouds. The upwelling radiation is converted to brightness temperatures and used to measure the intensity of the TC\u27s warm core, precipitation, and ice particle formation via the emitted radiation absorption and scattering signatures. Currently, operational TC prediction centers rely on intensity estimates derived from Polar-orbiting Operational Environmental Satellite (POES) Advanced Microwave Sounding Unit (AMSUA) brightness temperatures. This study compares the performance of a variety of TC intensity estimation techniques using both the imaging and sounding channels from AMSUA, the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager and Sounder (SSMI/S), and the Suomi-National Polar-orbiting Partnership (S-NPP) Advanced Technology Microwave Sounder (ATMS) for a sample of 28 North Atlantic storms from the 2011 through 2013 TC seasons

Emerging Hydro-Climatic Patterns, Teleconnections and Extreme Events in Changing World at Different Timescales

This Special Issue is expected to advance our understanding of these emerging patterns, teleconnections, and extreme events in a changing world for more accurate prediction or projection of their changes especially on different spatial–time scales

Observational and modeling studies of oceanic responses and feedbacks to typhoons Hato and Mangkhut over the northern shelf of the South China Sea

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Dong, W., Feng, Y., Chen, C., Wu, Z., Xu, D., Li, S., Xu, Q., Wang, L., Beardsley, R. C., Lin, H., Li, R., Chen, J., & Li, J. Observational and modeling studies of oceanic responses and feedbacks to typhoons Hato and Mangkhut over the northern shelf of the South China Sea. Progress in Oceanography, 191, (2021): 102507, https://doi.org/10.1016/j.pocean.2020.102507.Meteorological and oceanic responses to Typhoons Hato and Mangkhut were captured by storm-monitoring network buoys over the northern shelf of the South China Sea. With similar shelf-traversing trajectories, these two typhoons exhibited distinctly different features in storm-induced oceanic mixing and oceanic heat transfer through the air-sea interface. A well-defined cold wake was detected underneath the storm due to a rapid drop in sea surface temperature during the Hato crossing, but not during the Mangkhut crossing. Impacts of oceanic mixing on forming a storm-produced cold wake were associated with the pre-storm condition of water stratification. In addition to oceanic mixing produced through the diffusion process by shear and buoyancy turbulence productions, the short-time scale of mixing suggested convection/overturning may play a critical role in the rapid cooling at the sea surface. The importance of convection/overturning to mixing depended on the duration of atmospheric cooling above the sea surface-the longer the atmospheric cooling, the more significant effect on mixing. Including the oceanic mixed layer (OML) in the WRF model was capable of reproducing the observed storm-induced variations of wind and air pressure, but not the air and sea surface temperatures. Process-oriented numerical experiments with the OML models supported both observational and modeling findings. To simulate the storm-induced mixing in a coupled atmospheric and oceanic model, we need to improve the physics of vertical mixing with non-hydrostatic convection/overturning. Warming over the shelf is projected to have a more energetic influence on future typhoon intensities and trajectories.This work was supported by the National Key Research and Development Programs of China with grant numbers 2018YFC-1406201; 2016YFA-0602700; 2018YFC-1506903; 2018YFC-1406205, and the National Sciences Foundation of China with grant number U1811464. S. Li was supported by the oversea Ph.D. fellowship from the China Scholarship Council (No. 1409010025) and Dr. Chen’s Montgomery Charter Chair graduate education funds at the University of Massachusetts-Dartmouth

Oceanic response to the consecutive Hurricanes Dorian and Humberto (2019) in the Sargasso Sea

Understanding the oceanic response to tropical cyclones (TCs) is of importance for studies on climate change. Although the oceanic effects induced by individual TCs have been extensively investigated, studies on the oceanic response to the passage of consecutive TCs are rare. In this work, we assess the upper-oceanic response to the passage of Hurricanes Dorian and Humberto over the western Sargasso Sea in 2019 using satellite remote sensing and modelled data. We found that the combined effects of these slow-moving TCs led to an increased oceanic response during the third and fourth post-storm weeks of Dorian (accounting for both Dorian and Humberto effects) because of the induced mixing and upwelling at this time. Overall, anomalies of sea surface temperature, ocean heat content, and mean temperature from the sea surface to a depth of 100 m were 50 %, 63 %, and 57 % smaller (more negative) in the third-fourth post-storm weeks than in the first-second post-storm weeks of Dorian (accounting only for Dorian effects), respectively. For the biological response, we found that surface chlorophyll a (chl a) concentration anomalies, the mean chl a concentration in the euphotic zone, and the chl a concentration in the deep chlorophyll maximum were 16 %, 4 %, and 16 % higher in the third-fourth post-storm weeks than in the first-second post-storm weeks, respectively. The sea surface cooling and increased biological response induced by these TCs were significantly higher (Mann-Whitney test, p < 0.05) compared to climatological records. Our climatological analysis reveals that the strongest TC-induced oceanographic variability in the western Sargasso Sea can be associated with the occurrence of consecutive TCs and long-lasting TC forcing