Funded Projects

Program (s): Climate Variability & Predictability

Competition: Pre-Field Modeling Studies in Support of TPOS Process Studies, a Component of TPOS 2020

Award Number: NA18OAR4310402 | View Publications on Google Scholar

Objectives: Our interests are in understanding the complex processes that control the distribution of salinity in the ocean boundary layer (OBL) over a wide range of spatial and temporal scales, including both oceanic and atmospheric processes. Our investigation would utilize existing data sets taken in the eastern Pacific Ocean during the SPURS-2 field campaign combined with simulations and numerical modeling. The project seeks to answer questions regarding the relative importance precipitation, evaporation, diurnal variability, temperature stratification and barrier layers play on the OBL structure and upper ocean mixing processes, and how this variability affects air-sea exchanges of heat, freshwater, and momentum and resulting atmospheric convection and precipitation. The results of this investigation will then be used to answer the following questions: What measurements would be required to shed light on these processes at the frontal region of the warm/fresh pool? What measurements would be needed to improve the way we parameterize these processes in coarser-resolution models? Relevance of Proposed Research: The overall objective of the “Air-Sea Interaction at the eastern edge of the Warm Pool” is to better understand the impact of air-sea interaction and the upper ocean salinity stratification in maintaining the warm SSTs at the eastern edge of the west Pacific warm pool. Our interests are in understanding the complex processes that control the distribution of salinity in the ocean boundary layer over a wide range of spatial and temporal scales, including both oceanic and atmospheric processes using observations and a hierarchy of modeling approaches, directly in line with CVP Program priorities. The results of this research are aimed specifically at providing information on the atmospheric and oceanic observations needed and the time and space scales required to adequately capture the relevant processes of interest in maintaining the temperature and salinity stratification in the eastern edge of the west Pacific warm pool region. Further, this research is directly related to the goal of gaining a process-level understanding of how the atmosphere-ocean system interacts, a major goal of the CVP Program. Summary of Work: Our proposed work will include: (1) analysis of the comprehensive oceanic and atmospheric data sets from the SPURS-2 field campaign in light of our research questions and comparisons of these data with our model simulations; (2) simulations using cloud-resolving large eddy simulation (LES) models coupled to a mixed layer ocean model to examine how convective precipitation produces stratified, fresh water regions and the evolution of these fresh regions over time; (3) evaluation of wind- and buoyancy-forced OBL mixing processes using high-resolution ocean LES and one-dimensional turbulence models initialized with measured and modeled vertical structure and surface fluxes, and (4) recommendations based on these results for important measurements and associated time and space scales for the TPOS warm/fresh pool study to provide further insight into the oceanic and atmospheric processes occurring in that region.

Program (s): Climate Variability & Predictability

Competition: Observation and Modeling Studies in Support of Tropical Pacific Process Studies, Pre-Field-II

Award Number: NA22OAR4310623 | View Publications on Google Scholar

Our interests are in understanding the key features needed to more accurately represent both atmospheric and oceanic boundary layer processes, which are crucial for robust prediction of tropical atmosphere-ocean interactions. To do this we need to understand the structure of the boundary layers and develop a plan for measurement that fits both the scale of active processes and the needs of parameterization development. Our investigation would utilize existing tropical data sets and numerical modeling. The goal of this proposal is to use the sensitivity of coupled models to changes in boundary layer resolution and parameterizations as a tool to develop a field measurement strategy. We hypothesize that determining the correct resolution and parameterization for representing a process in a model provides a first estimate of resolution needs of measurements. With model results for guidance, we plan to provide metrics for various measurement platforms that will hone in on both the correct resolution and type of instrument array. Our experiments will also help in developing the overall observation strategy. Relevance and Broader Impacts of Proposed Research: The overall objective of the “Air-Sea Interaction at the eastern edge of the Warm Pool” is to better understand the impact of air-sea interaction and the upper ocean salinity stratification in maintaining the warm SSTs at the eastern edge of the west Pacific warm pool. Our interests are in understanding the complex processes that control the coupled atmosphere-ocean boundary layers in this region, using observations and a hierarchy of modeling approaches, directly in line with CVP Program priorities. The results of this research are aimed specifically at providing information on the atmospheric and oceanic observations needed and the time and space scales required to adequately capture the relevant processes of interest in maintaining the temperature and salinity stratification in the eastern edge of the west Pacific warm pool region. Further, with our focus on the impacts of coupling on convection and precipitation in this region, the research is directly related to improving understanding and representation of the structure of precipitation in this key region for global precipitation predictability, supporting NOAA’s Precipitation Prediction Grand Challenge. Our proposed work will include analysis from observations and uncoupled and coupled models of: (1) impacts of flux parameterizations on the upper ocean and the coupled system; (2) evaluation of the effects of including wave data into upper ocean processes, fluxes, and coupled feedbacks; (3) simulations using cloud-resolving large-eddy simulation (LES) models coupled to a mixed layer ocean model to evaluate the impact of vertical ocean model resolution on key processes; (4) simulations using coupled WRF-ROMS models to evaluate the impact of vertical atmospheric model resolution on key convective processes (e.g. cold pools); (5) usefulness of parameterizations of diurnal SST warming and changes in upper ocean salinity due to precipitation in reproducing the coupled system, and (6) recommendations of metrics for various measurement platforms that will hone in on both the correct resolution and type of instrument array needed to accurately capture processes relevant for air-sea interaction in the tropical Pacific.

Program (s): Climate Variability and Predictability

Competition: Understanding Arctic Sea Ice Mechanisms and Predictability

Award Number: NA15OAR4310161 | View Publications on Google Scholar

Predictions of sea ice on subseasonal to interannual timescales has the potential to be of widespread value if they are skillful at the lead times and spatial scales needed by forecast users. Understanding sea ice predictability is needed for high-stakes decision-making, such as arises in shipping, accessing resources, and protecting Arctic communities. Current prediction efforts have focused mainly on predicting total northern hemisphere sea ice extent (SIE), termed pan-Arctic SIE. To succeed at predicting regional scales requires significant new effort in three key areas. First, data assimilation techniques must be advanced to accurately initialize sea ice and other components at proper spatial scales. Second, metrics are needed to quantify the skill at the relevant spatial scales and for patterns of interest. Identifying key metrics is motivated by the expectation that a forecast system can't be improved without first developing adequate metrics for evaluating the features of importance. And third, effective statistical post processing methods are needed to correct for systematic biases in the resulting forecasts and to compute forecast probability.

We propose to investigate methods and develop the tools needed to address these three issues in building successful forecast systems. We propose to conduct our research in a well- studied, state-of-the-art sea ice component that is part of a global climate model. To turn this global model into a premier sea ice forecast system, we will work with Jeffrey Anderson and Nancy Collins and the NCAR Data Assimilation Research Testbed to implement DART to assimilate sea ice observations.

With this data assimilating forecast system, we will develop new evaluation metrics to investigate which observations are most essential among in situ measurements (including buoy and ship-based data) and remote sensing. We plan to investigate which regions are most predictable and what mechanisms (including mechanisms that involve coupling between ice, ocean and atmosphere) are responsible. Another important part of our project is to compare predictability in our system to others. We will undertake this with our links to the Sea Ice Outlook project and by providing our research on new metrics to evaluate regional patterns to other modeling centers for detailed intercomparisons. We have plans to collaborate directly with Rym Msadek and colleagues at GFDL to undertake a detailed comparison between the two premier U.S. global climate models, which have the most advanced sea ice components and high fidelity in the Arctic Ocean and atmosphere simulations. We also have discussed collaborating with Pablo Clemente-Colon, Chief Scientists at the National Ice Center, to better address sea ice forecast users needs in the metrics of local and regional-scale sea ice that we develop.

Our project has direct relevance to NOAA CVP Competition by exploring the value of assimilating sea ice observations, developing metrics that evaluate spatial distributions relevant to sea ice, and investigating mechanisms of regional sea ice variations. Our project is aligned with NOAAs goal of improving future operational predictions on time scales of a few months to decades. Our system will be capable of informing future data acquisition.

Program (s): Climate Variability & Predictability

Competition: Observation and Modeling Studies in Support of Tropical Pacific Process Studies, Pre-Field-II

Award Number: GC22-206 | View Publications on Google Scholar

The air-sea transition zone (the upper ocean, air-sea interface, and atmospheric marine boundary layer) represents the physical space where air-sea interaction takes place. The perspective of the air-sea transition zone (ASTZ) advances the conventional concept of air-sea interaction at the air-sea interface to include both the oceanic and atmospheric boundary layers, which responds to and influences air-sea fluxes of energy, momentum, and mass. Studying the ASTZ acquires collocated and simultaneous observations of the ocean-atmosphere profiles of the entire ASTZ and seamless coupling of the atmosphere and ocean through the ASTZ in the Earth system models. Traditionally, observing the ASTZ has been done using ships and aircraft, which are expensive and logistically difficult. The recent rapid development of autonomous observing technologies opens the door to observe the ASTZ using uncrewed underwater, surface and aerial vehicles. This proposed research intends to investigate the feasibility and requirement of using uncrewed mobile platforms to observe the ASTZ. We propose to conduct our investigation through developing a virtual sampling framework using combined uncrewed systems (CUSs). In this framework, high-resolution coupled ocean-wave-atmosphere model simulations will be sampled by virtually deploying underwater gliders, saildrones, and aerial drones in coordination. Because the motions of the CUS components depend on wind, sea state, and current conditions, the design and navigation of their positions and tracks to be close to each other will have to be done based on past deployment experience of their motion characteristics. The virtually sampled data will be placed in the contest of the full simulations to assess the requirements to adequately represent the structure and variability of the ASTZ on various scales in real deployment of a CUS. The requirements include, but are not limited to, sampling locations, time, frequency, duration, vertical extents, horizontal coverage, etc. The virtual sampling framework will be conducted in the tropical Pacific, particularly over the eastern edge of the warm pool and the equatorial ITCZ/cold tongue region under various weather and climate conditions (e.g., phases and stages of the MJO and ENSO). This proposed study builds upon the PI team’s collective expertise in air-sea interaction using in situ and remote sensing observations and coupled ocean-atmosphere models, and experience in field observations. The most direct beneficiary of this study would be the future field campaign on Air-Sea Interaction at the Eastern Edge of the Pacific Warm Pool and Pacific Upwelling and Mixing Physics (PUMP). Results from this study will aid designs of these and other field campaigns that include observations of the ASTZ using CUSs as an objective to advance our understanding of component interactions of the Earth’s climate system and our ability of modeling and predicting climate variability to assist NOAA’s science and service mission.

Program (s): Climate Variability & Predictability

Competition: Observing and Understanding Upper - Ocean Processes and Shallow Convection in the Tropical Atlantic Ocean

Award Number: GC19-301 | View Publications on Google Scholar

In the region of the northwest tropical Atlantic, there are energetic ocean eddies. They are anticyclonic warm core eddies and cyclonic cold core eddies generated in the interior ocean propagating to the western boundary, and deep reaching North Brazil Current (NBC) Rings generated by the NBC retroflection. These eddies can have strong signatures in sea surface temperature (SST) and surface currents, and thus modulate surface latent and sensible heat fluxes and momentum flux. Possible roles of these eddies on air-sea coupling and atmospheric shallow clouds in the region are unknown. In January-February 2020, U.S. and European scientists will jointly conduct field observations of Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) and EUREC4A-OA (Elucidating the role of clouds-circulation coupling in climate – Ocean and Atmosphere) in the northwest tropical Atlantic east of Barbados. The goal is to understand the air-sea interaction in the region, focusing on mesoscale ocean eddies and their influences on atmospheric shallow convection and formation of shallow cumulus clouds. This proposed research is to participate in this field campaign by deploying two Saildrones that cover the campaign period and beyond for 180 days. The objective of the Saildrone deployment is to advance understanding of air-sea coupling associated with ocean eddies in this region through measuring their signals in SST, SSS, upper-ocean current profiles, surface air temperature, humidity, pressure, wind direction and speed, short- and long-wave radiation, and possibly cloud images. These Saildrone measurements will complement in situ measurements to be made by ships, aircraft and other autonomous devices and remote measurement by satellites during the field campaign. The advantage of the Saildrones is their controllable mobility and long duration, which would allow them to be steered to follow individual ocean eddies and to sample a large number of eddies. The proposed Saildrone deployment during the ATOMIC-EUREC4A-OA campaign directly responds to the CVP solicitation for proposals that focuses on observing, understanding, and/or process modeling of upper ocean processes and air-sea interactions in the Northwest Tropical Atlantic. The proposed effort directly contributes to the first two objectives of NOAA’s long-term climate goals as described in NOAA’s Next-Generation Strategic Plan (NGSP): 1) Improved scientific understanding of the changing climate system and its impacts; 2) Assessment of current and future states of the climate system that identify potential impacts and inform science, service, and stewardship decisions.

Program (s): Climate Variability & Predictability

Competition: Observing and Understanding Processes Affecting the Propagation of Intraseasonal Oscillations in the Maritime Continent Region

Award Number: GC17-304 | View Publications on Google Scholar

The barrier effect of the Indo-Pacific Maritime Continent (MC) on the MJO is one of the major problems challenging the MJO study and prediction. Reasons for the weakening of the MJO over the MC and for some MJO events to fail to propagate through the MC remain unknown. Recent observations and model simulations suggest two factors that may play key roles in this problem. One is the diurnal cycle of precipitation, the other the distribution of precipitation over land vs. water in the MC region. They are related. Satellite observations have shown that MJO events propagate through the MC only when their convection over water in the MC region is sufficiently developed, and they would stall over the MC and fail to reemerge on the Pacific side if land-locked convection dominates. Numerical simulations have demonstrated that a strong diurnal cycle would promote land-locked convection and enhance the barrier effect of the MC on the MJO. Precipitation data of fine temporal/spatial resolutions and high accuracy are needed for observational diagnostics and validation of cloud-permitting model simulations to further our understanding of these and other possible mechanisms for the MC barrier effect. We propose to produce a precipitation dataset for the MC region at high resolutions in time (30 min) and space (8 km x 8 km) (potentially 15 min and 0.05 degrees latitude/longitude). This new precipitation data will be based on satellite passive microwave (PMW) trievals augmented by ground measurement of rain gauges and quantitative precipitation estimate (QPE) from radar observations in the MC region. With incorporated ground observations and satellite retrievals, this product will provide more accurate estimate of the diurnal cycle and land-sea distribution of precipitation than any currently available precipitation data. We will use this data set to diagnose the diurnal cycle and land-sea distributions of convection over the MC during YMC. The diagnosis would identify individual precipitating cloud clusters (their sizes, height, and rain rates) within and outside MJO large-scale convective envelopes, their diurnal cycle, and their spatial variability in the MC. The proposed precipitation data and their analysis in this project will provide powerful tools for evaluations of cloud permitting model simulations for YMC, as well as for advancing our understanding of potential roles of the diurnal cycle and land-sea distributions of precipitation in the MC barrier effect on the MJO. The proposed data will be made available for YMC PIs as they are produced and for public use one year after the end of YMC. The proposed research directly responds to the CVP solicitation for proposals “that aim to improve understanding of processes that affect the propagation (speed, intensity, disruption, geographic placement) of intraseasonal oscillations in the Maritime Continent and broader region by using a combination of in situ and remote observations, data analysis, modeling, and/or theoretical understanding of local and remote processes”.

Program (s): Climate Variability and Predictability

Competition:

Award Number: NA13OAR4310161 | View Publications on Google Scholar

This proposed research plans to address two issues that emerged from the DYNAMO field campaign: possible roles of the ITCZ and the Maritime Continent in MJO initiation. The pre-onset phases of the two MJO events (in October and November 2011) during the field campaign were characterized by active ITCZ south of the equator. The convective onset or initiation of each MJO event was marked by a shift of the ITCZ toward the equator. Preliminary diagnostics indicate that the ITCZ and its northward movement were present during about 50% of convective initiation events of the MJO over the Indian Ocean since 1998. It is unknown whether the processes of MJO initiation with and without the ITCZ would be very different or the ITCZ is simply an extraneous feature during convective initiation of the MJO. Possible roles of the ITCZ in MJO initiation have never been studied and were not considered in DYNAMO science documents. They are relevant to DYNAMO Hypothesis II, because it would make a huge difference in evolution of cloud population statistics with or without the ITCZ during the pre-initiation phases of the MJO.

Another intriguing phenomenon observed during the DYNAMO field campaign is westward moisture advection into the tropical Indian Ocean from the Maritime Continent (MC) by low-level easterlies during the initiation of the two MJO events. The MC may act as a moisture source because of its almost perpetual precipitating convective clouds. The westward advection of moisture from the MC and its convergence over the equatorial Indian Ocean appear also in composites of past MJO events. This mechanism would be complementary to possible moistening by shallow convection that has been commonly assumed. The possible moistening by westward advection is relevant to DYNAMO Hypothesis I.

In this proposed research, the possible roles of the ITCZ and MC in MJO initiation will be investigated through diagnostics of long-term time series of satellite and reanalysis data, DYNAMO field observations, and ensemble forecast during the DYNAMO field campaign. In addition, numerical experiments will be performed to help explore the role of the MC in MJO initiation.

This proposal enters the 2013 competition of the NOAA Earth System Science (ESS) Program. It targets the ESS 2013 research priority of “Understanding and Improving Prediction of Tropical Convection using Results from the DYNAMO (Dynamics of the Madden-Julian Oscillation) Field Campaign”. The MJO is an important component of the tropical climate system. It affects many weather and climate phenomena globally, including their extreme events. By improving our understanding of the MJO and its initiation, this proposed research helps NOAA to achieve its longterm objective of “Improved scientific understanding of the changing climate system and its impacts”.

Program (s): Climate Variability & Predictability

Competition: Observing and Understanding Processes Affecting the Propagation of Intraseasonal Oscillations in the Maritime Continent Region

Award Number: GC17-301 | View Publications on Google Scholar

The Madison-Julian Oscillation (MJO) is a major source of variability and predictability in the equatorial ocean. The Indian Ocean is usually referred to as the birthplace of the MJO. As the MJO propagates to the East it encounters the Maritime Continent (MC) where it may die out, propagate into the Pacific Ocean, and/or trigger the Boreal Summer Intraseasonal Oscillation (BSISO). The BSISO propagates from the equatorial Maritime Continent northward over the Philippine Archipelago. Intraseasonal atmospheric variability offers the possibility of better 10-day predictions, yet its predictability remains elusive. Furthermore, the local response of the atmosphere-oceanland system to intraseasonal and synoptic atmospheric variability is not understood. The local response involves terrain blocking the flow, diurnal land sea breezes that locally enhance and/or interrupt synoptic-scale waves, and different surface feedbacks between the mostly vegetated land surface and the ocean mixed layer. The MJO-barrier is poorly captured in climate models; the reason is hypothesized to be associated with conflicting land vs oceanic convective diurnal cycles. To address this, NOAA and partners (ONR, NASA, DOE) are planning a major field and modeling study in the MC called Propagation of IntraSeasonal Tropical Oscillations (PISTON). We propose to make observations of ocean surface conditions, including fluxes of heat, moisture, and momentum, and the atmospheric boundary layer as part of PISTON in summer 2018 aboard a research vessel within the waters and the vicinity of the Philippine Archipelago. The research vessel permits us to sample different atmosphere-ocean interactions to incoming rain and wind events as a function of such parameters as distance offshore (0-300 km from shore), water depth, and island blocking of prevailing and anomalous wind. We expect nearshore diurnal circulations associated with the islands to superpose and interact with synoptic storm conditions propagating into the island regions. We will measure the ocean wave state, sea surface temperature, and turbulent fluxes of sensible and latent heat and momentum across the atmosphere-ocean interface. A unique array of in situ and remote sensing instruments continuously measures turbulence and its effects on the momentum, heat, water, and salinity budgets. Together the observing systems proposed for the ship vertically profile temperature, moisture, and turbulent velocities from the ocean mixed layer, through the air-sea interface, atmospheric surface and planetary boundary layer, to shallow clouds. Our measurements will be a major contributor to high resolution modelling performed by research partners at Oregon State University (already funded for PISTON).

Program (s): Climate Variability and Predictability

Competition:

Award Number: | View Publications on Google Scholar

This proposal is motivated by the societal need for skillful decadal forecasts of the West African Monsoon and its associated impacts on Hurricane Activity. It is also motivated by the need to increase our confidence in coupled Atmosphere-Ocean General Circulation Models (AOGCMs) used for longer time climate prediction – especially given the lack of model agreement in West African rainfall predictions in this region reported in the 4th Assessment Report of the Intergovernment Panel on Climate Change. 

The two overarching aims of the proposal are: 

(1) To evaluate the extent to which coupled ocean-atmosphere models are able to predict decadal variability of the West African climate including its impacts on hurricane activity. 

(2) To investigate the key mechanisms which explain identified decadal predictability of the West African climate as well as the reasons for model-to-model differences in skill. 

Succesfully addressing these aims is an important step towards establishing an operational decadal prediction system for use in the West African and Tropical Atlantic regions. The work planned will make extensive use of the “short-term” decadal forecasts made for CMIP5, with most effort given to the 10-year and 30-year hindcasts and forecasts. Objective measures of the skill of all available models will be prepared by comparing the forecasts with observations of West African rainfall, sea surface temperatures and reanalysis datasets. The analysis will highlight the extent to which state-of-the-art AOGCMs are able to predict the West African and Atlantic climate on decadal timescales and whether this depends on the state of the ocean. Efforts will be made to explain the sources of predictability in the most skillful models and to assess the extent to which the level of skill relies on realistic representation of monsoon processes in the West African region. Evaluation of the 30-year forecasts will also be used to assess the potential role of anthropogenic forcing on the WAM by exploring trends in rainfall and related trends in SSTs.

Program (s): Climate Variability & Predictability

Competition: Observing and Understanding Upper - Ocean Processes and Shallow Convection in the Tropical Atlantic Ocean

Award Number: GC19-302 | View Publications on Google Scholar

Above most of the oceans, liquid clouds of a few thousand meters or less drive mixing in a process called shallow convection in the atmospheric boundary layer (ABL). The warm clouds dominate the ocean’s area coverage and may strongly influence weather on seasonal to sub-seasonal time scales. Shallow convection exerts an important influence on sea surface temperatures (SSTs) and salinity by moderating the air-sea exchanges of energy and moisture and represent a ‘major source of uncertainty in projections of future climate’. The interaction between shallow convection and the ocean’s surface layers is a two-way street: though shallow convection influences SSTs, shallow convection is itself controlled to a large extent by SST and air-sea fluxes, which are mediated by processes within the ocean, especially Oceanic Barrier Layers (OBL) and mesoscale ocean eddies. OBL are near-surface layers created by low salinity waters and embedded in the ocean mixed layer. OBLs tend to decouple the ocean mixed layer from surface momentum fluxes, which facilitates subsurface warming as short wave radiation penetrates to the base of the OBL. Both eddies and OBL can influence weather and climate patterns. In this project we propose to investigate the structure and dynamics of shallow convective boundary layers and their coupling to oceanic variability and mixing via ship-based surface flux and atmospheric boundary layer observations during the Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC). We propose continuous sampling aboard a research vessel that operates east of Barbados during the ATOMIC field program. The observing systems will be similar to those deployed in NOAA’s recent DYNAMO and PISTON studies. The ship will sample the atmosphere and ocean in the context of a larger array of ships and aircraft in cooperation with the Elucidating the role of cloud-circulation coupling in climate (EUREC4A) field program. Using in situ sensors, unmanned aircraft (UAS), and vertically-pointing Doppler remote sensing, we will measure and characterize mesoscale and synoptic variability in the surface fluxes, ABL and cloud turbulence as convective systems pass over the ship. The large-scale forcing will be determined by a combination of ship-launched balloon soundings and aircraft dropsondes associated with the larger ATOMIC/EUREC4A programs. We expect to work closely with P. Zuidema (U. Miami), S. de Szoeke (OSU), G. Feingold (NOAA/CSD) and P. Sullivan (NCAR) on LES modeling of the oceanic and atmospheric boundary layer and ABL-cloud interactions. The combination of LES and UAS plus radar-lidar velocity profiles will allow us to examine local gradient vs non-local (mass flux) boundary-layer flux profile parameterizations. We will coordinate with PMEL (Quinn) on UAS and aerosols observations. We will work with E. Thompson (APL-US) and J. edson (WHOI) on connecting atmospheric forcing with oceanic response. We will coordinate with the NOAA P-3 aircraft to set the mesoscale context of the ship observations. The P-3 will deploy dropsondes and AXBT (S. Chen NRL) and it will host the PSD Airborne Doppler W-band radar and the WSRA ocean surface wave radar.