Funded Projects

   Search     
Enter Search Value:
- without any prefix or suffix to find all records where a column contains the value you enter, e.g. Net
- with | prefix to find all records where a column starts with the value you enter, e.g. |Network
- with | suffix to find all records where a column ends with the value you enter, e.g. Network|
- with | prefix and suffix to find all records containing the value you enter exactly, e.g. |Network|

State estimates for the tropical Pacific: a reanalysis for evaluating the model, observations, and mass, heat, and salt fluxes

Principal Investigator(s): Bruce Cornuelle (Scripps), Co-Investigator: Ariane Verdy (Scripps)

Year Initially Funded: 2018

Program (s): Climate Variability & Predictability

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

Award Number: NA18OAR4310403 | View Publications on Google Scholar


The First Report of TPOS 2020 (Tropical Pacific Observing System 2020, tpos2020.org) recommended several process studies, including Pacific Upwelling and Mixing Physics (PUMP), and Air-sea Interaction at the eastern edge of the Warm Pool (WPEE). We are proposing a modeling and assimilation study in support of these process studies, at the large-scale end of an expected hierarchy of models. The state estimates will form a reanalysis for siting smaller-scale studies and the adjoint model can be used to probe sensitivities that can inform sampling. Data withholding experiments will also be performed to assess the values of different components of the observing systems, as well as their usefulness for testing and improving models. The overall goal of these studies is to improve the ocean models and initializations for better predictability of the coupled Pacific climate system in support of better environmental prediction, to help refine the TPOS 2020 implementation, and to assess an assimilation system as a key component of the observing system. We will produce a series of overlapping Four-dimensional variational (4D-Var) state estimates for the tropical Pacific covering 2010-2019 at a resolution of 1/3 degree or better. Each estimate is a free forward model run that has had initial conditions, forcing, and other controls adjusted so that it is consistent with observations and can provide diagnoses of mass, heat, and salt fluxes. They will be used to support embedded process studies and to assess regions of good and bad model skill to provide guidance for model improvement and designing observing systems. The model domain will include the entire tropical Pacific, and so will contain both the PUMP upwelling region and the warm pool region. We will work collaboratively with the NOAA labs and other investigators to provide a dynamically-consistent, property-conserving, large-scale context and boundary conditions for the hierarchy of process models as mentioned in the Call. The state estimates will enforce the model dynamics over assimilation windows of up to 4 months or longer, to be determined experimentally as part of the research. Each fit tests the model as a hypothesis for the dynamical explanation of the observations, and the controls estimated as part of the assimilation process will be examined to identify model errors. Cross-validation will come from comparisons to withheld observations and from forecasts beyond the time range of each estimate. In this way, the assimilation serves as a process experiment by directly testing the compatibility of the proposed dynamics, as quantified in the model, with the observations. The state estimates can be used as part of a diverse set of methods and models to provide the outer context and large-scale budgets for the inner models.

Understanding Coupled Ocean-Atmosphere Processes at the Eastern Edge of the Warm Pool in Support of TPOS 2020

Principal Investigator(s): Shuyi Chen (University of Washington), Dongxiao Zhang (University of Washington), Meghan Cronin (NOAA/PMEL)

Year Initially Funded: 2018

Program (s): Climate Variability & Predictability

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

Award Number: NA18OAR4310401 | View Publications on Google Scholar


The eastern edge of the warm pool marks the boundary between the western Pacific warm pool, where large-scale winds converge to form deep convection, and the equatorial cold tongue water to the east, where trade winds prevail. During El Niño, the eastern edge of the warm pool migrates eastward, shifting the location of the deep convection with it. The purpose of this study is to use a high resolution coupled ocean-atmosphere model to 1) understand the ocean-atmosphere interactions that play a role in both affecting the sharpness of the front and causing it to migrate eastward during onset of the El Niño; and 2) investigate the observational needs that would help model development and improve prediction of El Niño onset. In this study, we use the high-resolution Unified Wave Interface-Coupled Model (UWIN-CM) to investigate the coupled ocean-atmosphere and upper ocean processes at the edge of the warm/fresh pool. UWIN-CM is a fully coupled ocean-atmosphere model with explicit coupling physics at the ocean-atmosphere interface, which is uniquely suited for studying the air-sea interaction processes. It consists the Hybrid Coordinate Ocean Model (HYCOM) and the Weather Research and Forecasting (WRF) model. It has been fully tested for real time prediction over the Gulf of Mexico since 2012. It is currently a primary modeling tool for studying the coupled ocean-atmosphere processes in the MJO over the Maritime Continent. HYCOM and WRF will be configured over the western Pacific domain with 41 layers and 1/12 degrees for the ocean and 45 vertical levels and 4 km grid spacing for the atmosphere. Its cloud-permitting capability at 4 km is critical for this study This proposed research is in response to the CVP solicitation -- Pre-Field Modeling Studies in Support of TPOS Process Studies, a Component of TPOS 2020, which “aim to determine the relevant processes that are important for the ENSO development and their spatial and temporal scales need to be resolved in models and observations”. Results from this project would provide a better understanding and quantitative assessment on possible sources of the ENSO prediction barrier problem in numerical models. This would guide the strategy of TPOS 2020 observations in general, and help fulfill NOAA’s long-term climate goal of improved scientific understanding of the changing climate system and its impacts, and address challenges in weather and climate extremes.

Understanding Processes Controlling Near-Surface Salinity in the Tropical Ocean using Multiscale Coupled Modeling and Analysis

Principal Investigator(s): Carol Anne Clayson (WHOI), James Edson (WHOI), Eric Skyllingstad (Oregon State University)

Year Initially Funded: 2018

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.

Controls on upper ocean processes that impact intraseasonal variability in the Maritime Continent Region

Principal Investigator(s): Kelvin Richards (University of Hawaii)

Year Initially Funded: 2017

Program (s): Climate Variability & Predictability

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

Award Number: NA17OAR4310252 | View Publications on Google Scholar


Multi-scale interactions in the coupled ocean/atmosphere of the tropics play a crucial role in shaping the climate state and its spatial and temporal variability. On intraseasonal time scales (20-120 days) the Madden-Julian Oscillation (MJO) is the major player in affecting local and far-field conditions. Operational forecasts of the MJO show a significant reduction in skill as MJO events propagate over the the Maritime Continent, the so-called Maritime Continent MJO prediction barrier. Recognizing the importance of the Maritime Continent, the international project the Years of the Maritime Continent (YMC, July 2017 – July 2019) has as a major goal the improvement of the understanding and prediction of the MJO as it interacts with the Maritime Continent through an intensive field campaign and associated modeling studies. The present proposal focuses on identifying the major factors controlling the sea surface temperature, SST, in the Maritime Continent region. Variability of SST on intraseasonal to seasonal timescales strongly influences the maintenance and propagation of the MJO in the region with potential feedbacks between the atmosphere and ocean. In order to make a fair assessment of the role of the ocean in the maintenance and propagation of MJOs over the Maritime Continent in coupled models it is necessary to determine how well the ocean component of the coupled system is capturing the ocean state. A combination of observations and models will be used to determine the physical processes that influence the response of the upper ocean and SST to intraseasonal to seasonal variability of the atmosphere in the Maritime Continent region. A major focus will be salinity, its influence on the stratification of the upper ocean and associated warming of the surface ocean. The factors influencing the presence of fresh surface layers, their temporal and spatial scales, and impact on SST will be ascertained. We will also determine what it takes for a model to capture their impact properly. The results will be used as a guide to improve ocean/atmosphere interactions in coupled models. The potential of improving the simulation and prediction of MJO in models, with focus on the Maritime Continent region, and the associated societal benefits, underlie the goals of this proposal. As such the proposal is directly related to the aims of the NOAA CVP program – Observing and understanding processes of intraseasonal oscillations in the Marine Continent Region. Improving the present day MJO in models also applies to assessing the changes to MJO activity, and its impact on the monsoons and tropical cyclones, brought about by climate change. The proposal, therefore is also aligned with the climate objectives outlined in NOAA’s Next Generation Strategic Plan (NGSP, 2010), namely: Improved scientific understanding of the changing climate system and its impacts.

Convective multi-scale interactions over the Maritime Continent during the propagation of the MJO

Principal Investigator(s): Courtney Schumacher (Texas A&M University); BMKG radar team

Year Initially Funded: 2017

Program (s): Climate Variability & Predictability

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

Award Number: NA17OAR4310258 | View Publications on Google Scholar


Models have difficulty in simulating and predicting the evolution of the MJO as it crosses over the Maritime Continent (MC) because of the intricate convective-environmental interactions over the complex geography of the region. Land and ocean differences in the region lead to a strong diurnal cycle in rainfall over land that varies in character during the propagation of the Madden-Julian Oscillation (MJO). The hypothesis of this work is that the diurnal cycle over land disrupts the convective evolution in the MJO envelope and that the MJO has to overcome this strong diurnal signal to make it through the MC unscathed. The operational Indonesia Meteorological, Climatological and Geophysical Agency (BMKG) radar network consists of more than 30 single-polarization, Doppler C-band radars spread across the Indonesian islands. We will work with BMKG to collect and analyze high=resolution reflectivity and radial velocity observations from this network for all of 2018 to study storm structure variations across the MC during different phases of the MJO. In particular, we will determine whether there are variations in diurnal cycle rain intensity and organization before, during, and after the passage of the MJO convective envelope and how the MJO convective envelope responds to strong versus weak diurnal cycles over land. While these relationships have been studied with radars at individual sites, the tremendous extent of the BMKG radar network allows a much more comprehensive analysis of diurnal-intraseasonal interactions. In addition, results from satellite studies of these relationships are highly dependent on the limited sampling (e.g., once per day swaths) and/or proxy nature (e.g., outgoing longwave radiation) of measurements made from space. Rain mosaics from the radar network will further be used to assess large-scale model output, such as rain statistics throughout the diurnal cycle and over complex topography, both of which vex coarser resolution models, and can be assimilated into high-resolution regional models for enhanced analysis of the atmosphere over the MC. This work will also include science and technology exchange and capacity building with BMKG through interactions with their Division for Remote Sensing Imagery Management. This work is highly relevant to the objective of the Competition “Climate Variability and Predictability Program (CVP) – Observing and Understanding Processes Affecting the Propagation of Intraseasonal Oscillations in the Maritime Continent Region” by providing detailed observations of the evolution of convection across the Indonesian islands, which will help understand the scale interactions at play as the MJO traverses the complex geography of the MC and the associated land-ocean variability in storm structure and circulations, including very complicated diurnal cycles. It will also provide upstream convective conditions over much of the MC during PISTON. This work supports NOAA’s long-term climate goals by providing information on how detailed “scale-aware” parameterizations need to be to accurately model and predict the MJO propagation over the MC. Improvements in MJO model predictions and their subsequent impact on US circulation patterns can lead to improved prediction of US precipitation at sub-seasonal to seasonal (S2S) timescales.

High-Resolution Precipitation Product and Analysis for YMC

Principal Investigator(s): Chidong Zhang (NOAA/PMEL); Pingping Xie (NOAA/NCEP/CPC), Robert Joyce (NOAA/NCEP/CPC), and Brandon Kerns (U. Washington); Iddam Hairuly Umam (BMKG); Reza Bayu Perdana (BMKG)

Year Initially Funded: 2017

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”.

Identifying the Relative Roles of Precursors Associated with Observed versus Modeled MJO Propagation across the Maritime Continent

Principal Investigator(s): Naoko Sakaeda (University of Oklahoma); Juliana Dias (NOAA/PSL; Formerly U. Colorado/CIRES) and George Kiladis (NOAA/ESRL/PSL)

Year Initially Funded: 2017

Program (s): Climate Variability & Predictability

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

Award Number: GC17-302 | View Publications on Google Scholar


Tropical intraseasonal oscillations are key sources of sub-seasonal to seasonal predictive skill of the atmosphere, which represents a critical timescale for better preparing for potential weather-related risks. The Maritime Continent (MC) plays a critical role in sub-seasonal to seasonal predictive skill because intraseasonal tropical convection and the midlatitude jet stream interact strongly in this region, influencing subsequent weather downstream. This predictive skill is currently not fully realized because models struggle to accurately forecast and simulate tropical intraseasonal convective activity. One lingering model deficiency is that the MC tends to act as an unrealistically strong barrier for the eastward propagation of the Madden and Julian Oscillation (MJO) whereas, in reality, some developing MJO events propagate across the MC reaching the west Pacific basin. While several phenomena have been proposed to influence MC propagation of intraseasonal oscillations, their relative significance, interplay and precise mechanisms have not been examined in detail using observations, which is an essential step for model verification purposes. The proposed research will first examine observed MC propagation characteristics of the MJO such as speed, intensity, and how it is disrupted. Then, atmospheric and oceanic precursor signals that distinguish those characteristics will be investigated using multiple metrics to test the robustness of the results. The proposed research will also examine processes that control the occurrence of these precursor signals associated with MJO propagation and the mechanisms by which such precursors affect it, using global historical observational and reanalysis datasets along with in-situ observations from the Year of Maritime Continent (YMC) field campaign. The observational and reanalysis results will then be compared with the sub-seasonal to seasonal (S2S) project reforecast dataset to examine the fidelity of precursors signals associated with MJO propagation in the forecast models. Using the perturbed ensemble reforecast data, the final component of this research will investigate sources of forecast error and spread associated with MJO propagation. Along with the objectives of the Climate Variability Program competition, “Observing and Understanding Processes Affecting the Propagation of Intraseasonal Oscillations in the Maritime Continent Region”, the proposed project aims to identify the propagation characteristics of intraseasonal tropical convection across the MC and examine the processes controlling them using observational, reanalysis, and reforecast data. Tropical intraseasonal variability is known to influence frequency and location of extreme weather events. Therefore, improved understanding of intraseasonal tropical convection will ultimately help advance longrange forecast skill of extreme weather and climate projection skill of the frequency of extreme weather, which are important for achieving NOAA’s long-term goals of informing society to anticipate and respond to climate and weather impacts.

Influences of the Maritime Continent on the Eastward Propagation of the Madden-Julian Oscillation

Principal Investigator(s): Xianan Jiang (UCLA); Ming Zhao (NOAA/GFDL), Duane Waliser (UCLA/JPL), Baoqiang Xiang (NOAA/GFDL); Collaborator: Shian-Jiann Lin (NOAA/GFDL)

Year Initially Funded: 2017

Program (s): Climate Variability & Predictability

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

Award Number: NA17OAR4310261, GC17-307 | View Publications on Google Scholar


The Madden-Julian Oscillation (MJO) exerts significant influences on global weather extremes, and serves as a critical basis of the “Seamless Prediction” by bridging the forecasting gap between weather forecast and short-term climate prediction. However, the MJO remains poorly represented in the state-of-the-art general circulation models (GCMs) as well as NWP models. One particular challenge for modeling and predicting the MJO lies in its complex interaction with multi-scale convection over the Maritime Continent (MC). The eastward propagation of the MJO is often interrupted or weakened over the MC due to the so-called MC barrier effect, which is often exaggerated in climate models, thus significantly limiting our prediction skill for the MJO and associated weather extremes. Therefore, improved understanding of key processes on the interaction between the MC and the MJO becomes an urgent need to break this tropical prediction barrier. In this proposed study, with a team of researchers and modelers between UCLA and NOAA/GFDL, we propose to comprehensively investigate key processes associated with the MC influences on the eastward propagation of the MJO. Particularly, we will capitalize on a new generation climate model recently developed at GFDL with full capability of representing the observed MJO propagation features over the MC, and the unprecedented observations over the MC to be collected from the upcoming YMC (Years of the Maritime Continent) field campaign. Roles of multi-scale interaction, topography, large-scale mean state, and air-sea interaction for propagation of the MJO over the MC will be comprehensively characterized based on GFDL GCM in both climate simulation and hindcast modes. Identified model processes will be extensively validated by utilizing the YMC in-situ observations and satellite datasets along with global reanalyses. Additionally, multimodel hindcast dataset from the WWRP/WCRP Subseasonal-to-Seasonal (S2S) Prediction Project, will be also analyzed to establish a possible linkage of specific model deficiencies to the model “MC MJO prediction barrier” issue. This project is expected to provide significant insights into key processes regulating MJO propagation over the MC, thus leading to improved S2S prediction skill. This project will also directly benefit development of the GFDL GCM through comprehensive validation by the observations. This proposal is strongly relevant to one of the NOAA NGSP’s long-term goal, “toward an improved scientific understanding of the changing climate system”, by advancing core capabilities in “understanding and modeling” and “predictions and projections”, as well as societal challenges in “climate impacts on water resources” and “changes in extremes of weather and climate”. This proposal is also closely tied to several organized research activities currently being conducted by the WGNE MJO Task Force, the S2S Program, and is in line with recommendations by National Academy of Sciences on “Next Generation Earth System Prediction: Strategies for Subseasonal to Seasonal Forecasts”. In particular, this proposed research directly addresses CVP program’s FY2017 calls for “Observing and Understanding Processes Affecting the Propagation of Intraseasonal Oscillations in the Maritime Continent Region”.

Maritime Continent as a barrier to the MJO propagation: an analysis of the sensitivity of convection to column moisture

Principal Investigator(s): Zhiming Kuang (Harvard University); Collaborator: David Adams (Universidad Autonoma de Mexico)

Year Initially Funded: 2017

Program (s): Climate Variability & Predictability

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

Award Number: NA17OAR4310260 | View Publications on Google Scholar


We propose to conduct a comprehensive study of the hypothesis that the sensitivity of deep convection to column moisture is reduced over the Maritime Continent (MC), which leads to the Madden-Julian Oscillation (MJO) propagation barrier. It will include the following two components. 1. The first is an observational component that will make novel use of data obtained through Global Positioning System (GPS) measurements, currently the only all-weather water vapor measurements, from both satellite Radio Occultation missions and surface GPS stations. In particular, data collected by a network of 60 surface GPS stations over Sumatra for earthquake studies will be processed and introduced to the meteorological community. This will provide a unique multi-year dataset with high temporal resolution (5 minutes) and a spatial layout that is well suited for studying how major islands in the Maritime Continent modulate moist convection. We will then combine the GPS data, radiosonde data, and other available water vapor measurements, as well as in situ and satellite rainfall measurements, to characterize the sensitivity of convection to column moisture. Given that the strong diurnal cycle over land is likely a key process for the reduced sensitivity of convection to column moisture, we will further produce the first all-weather characterization of the diurnal cycle of column moisture over the Maritime Continent and its modulation by the MJO. 2. The observational results will be extended using cloud resolving model simulations with the Weather Research Forecast (WRF) model. Simulations with a range of model configurations, including resolution, will be evaluated against the observational results. The best model configurations will then be used to examine the reasons behind the reduced sensitivity of convection to column moisture and the MJO propagation barrier through detailed diagnostics and mechanism-denial experiments. The improved understanding can then be used to interpret behaviors of forecast models. Our work will produce a unique dataset that contributes to the observations of processes affecting the propagation of the MJO in the Maritime Continent region, as well as an improved understanding of these processes, thus directly address the objectives of this NOAA CVP program call. Given the importance of the MJO, this project will also support core capabilities of NOAA in understanding and modeling of the climate system.

Modulation of MJO-Diurnal Cycle Interaction over the Maritime Continent

Principal Investigator(s): Samson Hagos (PNNL, Battelle Memorial Inst.); Robert Joyce (NOAA/NCEP); Chidong Zhang (NOAA/PMEL); Collaborator: Agie Wandala Putra (BMKG)

Year Initially Funded: 2017

Program (s): Climate Variability & Predictability

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

Award Number: NA17OAR4310263, GC17-305 | View Publications on Google Scholar


The Maritime Continent (MC) is a major “prediction barrier” to the Madden-Julian Oscillation (MJO) because observed behaviors of MJO events are erratic over that region. Some MJO events slowly propagate eastward relatively unaffected, some weaken, and others stall and terminate over the MC. As a consequence, MJO forecast skills of the current generation of models are quite low there. Recent studies suggest this prediction barrier might not be intrinsic but rather a manifestation of model limitations related to lack of understanding and accurate representation of the processes that allow or block the propagation of MJO. For example, the disruption of MJO propagation by the MC is often exaggerated in many numerical models. Therefore understanding the processes that allow or impede MJO propagation across the MC is an important first step toward addressing the associated modeling and prediction difficulties. Our recent study shows that, via non-linear interactions between cloud processes and surface fluxes, diurnal cycle over the MC islands can weaken and stall propagating MJO convection signals. In this proposed study, we aim at investigating the processes that modulate this non-linear interaction and thereby explain why some events of the MJO cross the MC and others do not. We plan to use observations and cloud-permitting (3 km grid spacing) regional model simulations to tackle this issue. New high-resolution (15 minute, 0.05˚) precipitation data from passive microwave (PMW) sensors and surface and sounding data from Years of Maritime Continent campaign will be used to extensively document the diurnal cycle of precipitation as well as surface and atmospheric environmental conditions over and around the major islands of the MC before the arrival of MJO events that propagate through as well as those that are disrupted by the MC. These observations will be analyzed to assess the comparative roles of various environmental factors in the modulation of MJO-diurnal cycle interactions. Regional cloud permitting model simulations of the two groups of MJO events will be used to test hypotheses derived from the observations. We will individually swap initial land surface and lateral atmospheric conditions between the MJO events that successfully cross the MC and those that were disrupted. This would give us opportunities to isolate factors to which MJO propagation through the MJO is the most sensitive. The cloud-permitting model simulations will also be diagnosed to assess the extent to which information to be obtained from YMC/PISTON field observations at specific locations is applicable to other part of the MC. This proposal is a response to the FY 2017 Climate Variability and Predictability Program (CVP) and it targets the competition on the Observing and Understanding Processes Affecting the Propagation of Intra-seasonal Oscillations in the Maritime Continent Region. The proposed work is aligned with NOAA’s mission to enhance community resilience in the face of weather and climate extremes by extending lead times at which extreme events such as heat waves, drought, and flooding are skillfully predicted.



Page 7  of  18 First   Previous   3  4  5  6  [7]  8  9  10  11  12  Next   Last  

ABOUT US

Americans’ health, security and economic wellbeing are tied to climate and weather. Every day, we see communities grappling with environmental challenges due to unusual or extreme events related to climate and weather. 

CPO HEADQUARTERS

1315 East-West Highway Suite 100
Silver Spring, MD 20910