A5017501174- Climate variability and models
- Tropical and Extratropical Cyclones Research
- Meteorological Phenomena and Simulations
- Ocean Waves and Remote Sensing
- Oceanographic and Atmospheric Processes
- Atmospheric aerosols and clouds
- Precipitation Measurement and Analysis
- Aeolian processes and effects
- Scientific Computing and Data Management
- Atmospheric chemistry and aerosols
- Explainable Artificial Intelligence (XAI)
- Infrastructure Maintenance and Monitoring
- Atmospheric Ozone and Climate
- Asphalt Pavement Performance Evaluation
- Wind Energy Research and Development
- Plant Water Relations and Carbon Dynamics
- Geophysics and Gravity Measurements
- Methane Hydrates and Related Phenomena
- Solar and Space Plasma Dynamics
- Soil Moisture and Remote Sensing
- Computational and Text Analysis Methods
- Remote Sensing in Agriculture
- Agricultural risk and resilience
- Climate change impacts on agriculture
- Plant Ecology and Soil Science
University at Albany, State University of New York
2015-2024
Albany State University
2013-2022
NOAA Earth System Research Laboratory
2019
Physical Sciences (United States)
2019
Met Office
2003
University of Leeds
2003
European Centre for Medium-Range Weather Forecasts
2003
University of Reading
1994-2001
Abstract Two idealized baroclinic wave‐6 life cycles examined here suggest a framework of opposite extremes (a) in which to view the behaviour real synoptic‐scale disturbances middle latitudes, and (b) interrelate synoptic wave‐theoretic viewpoints, using ‘saturation‐propagation‐saturation’ (SPS) picture life‐cycle behaviour. The two cycles. dented by LC1 LC2, are higher‐resolution versions Simmons‐Hoskins ‘basic’ ‘anomalous’ cases (showing strong weak late decay eddy kinetic energy, EKE)....
African Monsoon Multidisciplinary Analysis (AMMA) is an international project to improve our knowledge and understanding of the West monsoon (WAM) its variability with emphasis on daily-to-interannual time scales. AMMA motivated by interest in fundamental scientific issues societal need for improved prediction WAM impacts nations. Recognizing develop strategies that reduce socioeconomic WAM, will facilitate multidisciplinary research required provide predictions impacts. This be achieved...
A significant number of tropical cyclones move into the midlatitudes and transform extratropical cyclones. This process is generally referred to as transition (ET). During ET a cyclone frequently produces intense rainfall strong winds has increased forward motion, so that such systems pose serious threat land maritime activities. Changes in structure system it evolves from an during necessitate changes forecast strategies. In this paper brief climatology given challenges associated with...
Abstract Analysis of the annually varying regional circulations and their relationship to surface conditions water vapour transport in West African region is presented. The progression monsoon described terms four key phases: (i) an oceanic phase between November mid‐April when rain band broad with peak values just north Equator (∼1°N); (ii) a coastal end June rainfall around 4°N (over ocean); (iii) transitional during first half July decreases; (iv) Sahelian mid‐July September more intense...
Automatic tracking of vorticity centers in European Centre for Medium-Range Weather Forecasts analyses has been used to develop a 20-yr climatology African easterly wave activity. The statistics at 600 and 850 mb confirm the complicated structures present over continent. rainy zone equatorward 15°N is dominated by 600-mb activity, much drier Saharan region poleward more 850-mb Over Atlantic Ocean there just one storm track with 600- activity collocated. Based on growth/decay genesis...
Abstract Using numerical model analyses, it is shown that there a coherent diurnal cycle of the West African monsoon winds. As has been observed in previous studies arid and semi‐arid areas, winds are at their weakest afternoon when convective boundary layer (CBL) deep, intensify overnight boundary‐layer turbulence much weaker. This maximized northern part layer, where meridional pressure gradient CBL both strong. The can also be resolved surface upper‐air data, which show how nocturnal...
Abstract The maintenance of the African easterly jet (AEJ) has been examined using a zonally symmetric general circulation model with simple parametrizations. It is shown that AEJ maintained in association two diabatically forced meridional circulations: one associated surface fluxes and dry convection Saharan heat‐low region deep moist intertropical convergence zone equatorward this. heating, which reaches height around 700 mb, particularly important maintaining its gradients potential...
Abstract The mean structure of African easterly waves (AEWs) over West Africa and the adjacent Atlantic is isolated by projecting dynamical fields from reanalysis radiosonde data onto space–time-filtered satellite-derived outgoing longwave radiation. These results are compared with previous studies an idealized modeling study in a companion paper, which provides evidence that bear close structural resemblance to fastest-growing linear normal mode summertime basic-state flow Africa. There...
Data from four recent reanalysis projects [ECMWF, NCEP–NCAR, NCEP–Department of Energy (DOE), NASA] have been diagnosed at the scale synoptic weather systems using an objective feature tracking method. The statistics indicate that, overall, reanalyses correspond very well in Northern Hemisphere (NH) lower troposphere, although differences for spatial distribution mean intensities show that ECMWF is systematically stronger main storm track regions but weaker around major orographic features....
Abstract The linear instability problem of the African easterly jet has been investigated using primitive equations on a sphere. This included an examination growth mechanisms and structure diagnostics traditionally employed for mid latitudes, such as Eliassen‐Palm (EP) fluxes potential vorticity. It shown that growing normal mode is characterized by divergent EP in region jet, implying both barotropic baroclinic energy conversions. dominated interaction between positive negative vorticity...
Abstract. The AMMA (African Monsoon Multidisciplinary Analysis) program is dedicated to providing a better understanding of the West African monsoon and its influence on physical, chemical biological environment regionally globally, as well relating variability this system issues health, water resources, food security demography for nations. Within framework, an intensive field campaign took place during summer 2006 document specific processes weather systems at various key stages season....
The life cycle of an intense African easterly wave (AEW) over the continent is examined using European Centre for Medium-Range Weather Forecasts (ECMWF) operational analyses, Meteosat satellite images, and synoptic observations. This system, strongest AEW 2000, can be tracked from central North Africa into eastern Atlantic Ocean, where it associated with genesis Hurricane Alberto. Synoptic analysis kinematic thermodynamic fields supplemented by potential vorticity (PV), allowing exploration...
The representation of tropical convection remains a serious challenge to the skillfulness our weather and climate prediction systems. To address this challenge, World Climate Research Programme (WCRP) Observing System Predictability Experiment (THORPEX) Weather (WWRP) are conducting joint research activity consisting focus period approach along with an integrated framework tailored exploit vast amounts existing observations, expanding computational resources, development new, high-resolution...
Abstract The association between convection and African easterly wave (AEW) activity over tropical Africa the Atlantic during boreal summer is examined using satellite brightness temperature (TB) ECMWF reanalysis datasets. Spectral analysis 18 yr of TB data shows significant variance in 2–6-day range across most region. Within regions deep convection, this time scale accounts for about 25%–35% total variance. convective has similar amplitudes western eastern Africa, while dynamic measures...
Abstract AMMA—the African Monsoon Multidisciplinary Analysis—is the biggest programme of research into environment and climate ever attempted in Africa. AMMA has involved a comprehensive field experiment bringing together ocean, land atmospheric measurements, on time‐scales ranging from hourly daily variability up to changes seasonal activity over number years. Many publications this special issue make use subsets collected diverse set sensors. As general introduction issue, paper provides...
Abstract This study uses models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) to evaluate and investigate Sahel rainfall multidecadal variability teleconnections with global sea surface temperatures (SSTs). Multidecadal is lower than observed in all historical simulations evaluated. Focus on North Atlantic SST [Atlantic (AMV)] as it more successfully simulated Indian Ocean teleconnection. To why some this teleconnection others did not, despite having similarly large AMV,...
Abstract The diurnal cycle of tropical convection and the cyclone (TC) cirrus canopy has been described extensively in previous studies. However, a complete understanding TC remains elusive is an area ongoing research. This work describes new technique that uses infrared satellite image differencing to examine evolution for all North Atlantic major hurricanes from 2001 2010. imagery reveals cyclical pulses cloud field regularly propagate radially outward storm. These begin forming storm’s...
Abstract A combination of observations and re‐analysis was used to investigate the mechanisms connection between Atlantic Multidecadal Oscillation (AMO) Sahel rainfall. composite technique based on AMO index identify differences warm cold phases AMO. significant summer rainfall increase over during observed, with large increases typical monsoon onset period in June. In spring prior onset, strengthening Saharan heat‐low its associated shallow meridional overturning circulation is observed....
Abstract A new Madden–Julian oscillation (MJO) index is developed from a combined empirical orthogonal function (EOF) analysis of meridionally averaged 200-hPa velocity potential (VP200), zonal wind (U200), and 850-hPa (U850). Like the Wheeler–Hendon Real-time Multivariate MJO (RMM) index, which was in same way except using outgoing longwave radiation (OLR) data instead VP200, daily are projected onto leading pair EOFs to produce two-component index. This called (VPM) indices its properties...
Abstract The New York State Mesonet (NYSM) is a network of 126 standard environmental monitoring stations deployed statewide with an average spacing 27 km. primary goal the NYSM to provide high-quality weather data at high spatial and temporal scales improve atmospheric prediction, especially for extreme events. As compared other networks, faced considerable deployment obstacles York’s complex terrain, forests, very rural urban areas; its wide range extremes; harsh winter conditions. To...
This paper provides for the first time an objective short-term (8 yr) climatology of African convective weather systems based on satellite imagery. Eight years infrared International Satellite Cloud Climatology Project–European Space Agency's Meteorological (ISCCP–Meteosat) imagery has been analyzed using feature identification, tracking, and statistical techniques July, August, September periods region Africa adjacent Atlantic ocean. allows various diagnostics to be computed used study...
The existence of African easterly waves (AEWs) north the jet (AEJ) core with maximum amplitude at low levels has been confirmed and clarified using radiosonde data U.K. Meteorological Office global model analysis from hurricane season 1995. At Bamako (12.5°N, 8.0°W) AEWs were characterized mainly by amplitudes level AEJ (around 700 mb), whereas Dakar (14.7°N, 17.5°W) maxima between 850 950 mb. low-level to arise in association baroclinic interactions negative meridional potential vorticity...
Analyses of the African easterly jet (AEJ) are presented which based on meridional transects high-resolution dropsonde observations made during JET2000, an aircraft campaign conducted in last week August 2000. The have confirmed that AEJ is closely defined by geostrophic balance. baroclinicity between extreme northern and southern profiles accurately determines altitude core, while location morphology core correspond to a locally-defined wind measure. potential-vorticity (PV) structure has...
Abstract This paper promotes the view that African easterly waves (AEWs) are triggered by localized forcing, most likely associated with latent heating upstream of region observed AEW growth. A primitive equation model is used to show AEWs can be finite-amplitude transient and on a zonally varying basic state linearly stable. Heating close entrance jet (AEJ) shown initiate downstream. The leads an initial trough reaches West coast about 5–7 days later, depending nature profile. After this,...