Key messages from "Dust, Convection, Winds, and Waves: The 2022 NASA CPEX-CV Campaign," by Edward P. Nowottnick (NASA Goddard Space Flight Center), Angela K. Rowe, Amin R. Nehrir, Jonathan A. Zawislak, Aaron J. Piña, Will McCarty, Rory A. Barton-Grimley, Kristopher M. Bedka, J. Ryan Bennett, Alan Brammer, Megan E. Buzanowicz, Gao Chen, Shu-Hua Chen, Shuyi S. Chen, Peter R. Colarco, John W. Cooney, Ewan Crosbie, James Doyle, Thorsten Fehr, Richard A. Ferrare, Steven D. Harrah, Svetla M. Hristova-Veleva, Bjorn H. Lambrigtsen, Quinton A. Lawton, Allan Lee, Eleni Marinou, Elinor R. Martin, Griša Močnik, Edoardo Mazza, Raquel Rodriguez Monje, Kelly M. Núñez Ocasio, Zhaoxia Pu, Manikandan Rajagopal, Jeffrey S. Reid, Claire E. Robinson, Rosimar Rios-Berrios, Benjamin D. Rodenkirch, Naoko Sakaeda, Vidal Salazar, Michael A. Shook, Leigh Sinclair, Gail M. Skofronick-Jackson, K. Lee Thornhill, Ryan D. Torn, David P. Van Gilst, Peter G. Veals, Holger Vömel, Sun Wong, Shun-Nan Wu, Luke D. Ziemba, and Edward J. Zipser. Published online in BAMS, November 2024. For the full, citable article, see https://doi.org/10.1175/BAMS-D-23-0201.1.
The tropical East Atlantic is a critical region for hurricane activity, yet we have gaps in our understanding of key processes linking the environmental conditions, aerosols like dust, and the convective storms owing to the lack of ground-based observations in this region and limitations of spaceborne instrumentation. This need motivated the NASA Convective Processes Experiment-Cabo Verde (CPEX-CV) field campaign based out of Cabo Verde during September 2022, where the region was sampled by the NASA DC-8 aircraft equipped with modern remote sensing and in situ observations. With 13 research flights, coupled with radiosonde launches from Sal Island, we sampled a variety of conditions and storm characteristics of this region through measurements of the dust-laden Saharan Air Layer (SAL), the boundary layer and its evolution, atmospheric dynamics, and convective systems across their lifecycles. These measurements were in turn used to inform processes and parameterizations used by mesoscale and global models for improved forecasts of Saharan dust transport and tropical convective storms, including an improved forecast for Tropical Storm Hermine when CPEX-CV observations were implemented into the model. This finding underscores the need for observations beyond our current spaceborne capabilities in this region to reliably improve forecast skill for developing tropical systems.
A focus of the campaign was to sample the vertical variability within the Saharan dust plume, through which our observations showed Saharan dust and the dry SAL can be decoupled. An additional key finding regarding dust is that observations suggest water uptake by dust particles originating from dry Saharan lake beds increases particle sphericity in humid environments. Furthermore, in situ observations highlighted the presence of giant-sized dust particles over the east Tropical Atlantic, indicating a mechanism responsible for keeping particles lofted that’s not currently captured in our aerosol modeling capabilities. Our flights also featured coincident measurements of convection in the vicinity of African Easterly Waves (AEWs) and the wave environments, providing rare observational evidence of intrusion of the dry SAL air near the wave’s circulation center that likely limited tropical cyclone genesis. These convection-environmental-AEW relationships were explored during afternoon flights in the first half of the campaign, while the latter half focused on early morning offshore convection. In one such case, CPEX-CV measurements showed enhancement of convection when synced with an AEW with influences of onshore monsoonal flow.
With our research, we showcase these cases in the context of the overall unique set of measurements CPEX-CV provided for understanding the complex coupling between convective life cycle, off-shore convection, Saharan dust outbreaks, the dry SAL, and tropical storm development in the tropical East Atlantic. These highlights are just the tip of the iceberg, and ongoing analysis leveraging the breadth of the CPEX-CV dataset will help uncover key processes responsible for the phenomena observed during the campaign that will improve our downwind forecasting capabilities in the tropical Atlantic. In addition to looking forward, our BAMS article provides the historical context for these unique measurements and emphasizes the professional development, team building, and contribution from unique individuals that make a campaign of this scale a success.
METADATA
BAMS: What would you like readers to learn from this article?
Edward Nowottnick (NASA Goddard Space Flight Center): I hope readers learn how sensitive the east tropical Atlantic is to perturbations that can drastically impact downwind development. The phenomena sampled by CPEX-CV in this complex region can be coupled or decoupled, making downwind forecasting particularly challenging in a data-sparse region. With this in mind, I hope readers appreciate how augmenting our current observation capabilities in the east tropical Atlantic can drastically improve our process-level understanding and forecast accuracy, as demonstrated by CPEX-CV, that underscores the future need for an enhanced, dedicated observing system in this region.
BAMS: How did you become interested in the topic of this article?
EN: I have always been interested in extreme weather. Growing up, I would binge watch the local news and the Weather Channel anytime an Atlantic hurricane would impact the United States or Caribbean. Fast forward to graduate school at The University of Maryland, my graduate research advisor (Pete Colarco) was (and still is), one of the world’s experts on dust modeling. I immediately became interested in how Saharan dust and the SAL could impact tropical storm development and continued that work into my post-doc position. During my post-doc, I was fortunate to participate in my first field campaign, the NASA Hurricane and Severe Storm Sentinel (HS-3) during 2012-2014, which kicked off my continued interest in using airborne capabilities to better understand atmospheric processes that cannot be learned from satellite or ground-based observations alone.
BAMS: What got you initially interested in meteorology or the related field you are in?
EN: Growing up in Maryland in the ‘90s, we were impacted by all sorts of extreme weather—thunderstorms, snowy blizzards (usually turning to rain when I blew off studying for an exam), and the occasional tornado and tropical storm. This piqued my interest in weather, particularly extreme weather, that I carried into adulthood. I thought I wanted to become a TV meteorologist, however, during my undergraduate studies, I interned with a local news meteorologist and quickly discovered I was more interested in the how and why we were seeing the phenomena we were forecasting. After this, I decided to go to graduate school for atmospheric science and the rest is history.
BAMS: What surprised you the most about the work you document in this article?
EN: What surprised me while in the field for this work was, despite leveraging meteorological and constituent forecast models and vast experience from our science team to fill out flight plans, the phenomena we were targeting would often develop differently overnight before we would wake up for our research flight. This happened across the board for the various phenomena we were targeting, but the Saharan dust outbreak sampled on our ninth research flight (RF09) on 22 September 2022 was particularly striking, as we woke up with this event right in our face. The planned primary focus of this flight was offshore convection, however, once we saw the magnitude of this dust event when visible imagery became available, we quickly pivoted to sampling the dust outbreak. Examples like this underscore the importance of having a cohesive, capable team to maximize science objective returns while in the field.
BAMS: What was the biggest challenge you encountered while doing this work?
EN: The biggest challenge I encountered while doing this work was during the planning phase of the CPEX-CV campaign. Scientists by nature often focus on their niche and a lot of effort was made with the team to understand everyone’s research objectives and how they tie into those of other scientists. While this required a lot of up-front work during the planning phase, our team development efforts paid off while in the field, as over and over, our team worked together to prioritize the overarching objectives of the campaign that led to the success of CPEX-CV.
BAMS: What’s next? How will you follow up?
EN: Since CPEX-CV, I’m currently the Radiation Sciences Program Manager within the Earth Science Division at NASA Headquarters, which historically has supported numerous NASA and interagency airborne field efforts. In this new role, I plan to continue this legacy and I am excited to help enable airborne campaigns in the future.
