Kara, A. B., Metzger, E. J., Hurlburt, H. E., Wallcraft, A. J., & Chassignet, E. P. (2008). Multistatistics metric evaluation of ocean general circulation model sea surface temperature: Application to 0.08° Pacific Hybrid Coordinate Ocean Model simulations. J. Geophys. Res. , 113 (C12).
Kara, A. B., Rochford, P. A., & Hurlburt, H. E. (2002). Air-Sea Flux Estimates And The 1997-1998 Enso Event. Boundary-Layer Meteorology , 103 (3), 439–458.
Kara, A. B., Wallcraft, A. J., Barron, C. N., Hurlburt, H. E., & Bourassa, M. A. (2008). Accuracy of 10 m winds from satellites and NWP products near land-sea boundaries. J. Geophys. Res. , 113 (C10).
Kara, A. B., Wallcraft, A. J., & Bourassa, M. A. (2008). Air-sea stability effects on the 10 m winds over the global ocean: Evaluations of air-sea flux algorithms. J. Geophys. Res. , 113 (C4).
Kara, A. B., Wallcraft, A. J., Martin, P. J., & Chassignet, E. P. (2008). Performance of mixed layer models in simulating SST in the equatorial Pacific Ocean. J. Geophys. Res. , 113 (C2).
Karmakar, N., & Misra, V. (2019). Differences in Northward Propagation of Convection Over the Arabian Sea and Bay of Bengal During Boreal Summer. J. Geophys. Res. Atmos. , 125 (3).
Abstract: The governing dynamics that modulate the propagation characteristics of intraseasonal oscillations (ISO) during summer monsoon over the two ocean basins, Bay of Bengal (BoB) and Arabian Sea (AS), are investigated using observational analysis and high‐resolution regional coupled ocean‐atmosphere climate model simulations. ISO features are extracted over the Indian region using a data‐adaptive spectral method called multichannel singular spectrum analysis. ISO exhibits stronger intensity over the BoB than over the AS. But ISO‐filtered rainfall propagates at a faster rate ( urn:x-wiley:jgrd:media:jgrd55983:jgrd55983-math-00011.25°/day) over AS as compared to BoB ( urn:x-wiley:jgrd:media:jgrd55983:jgrd55983-math-0002.74°/day), giving rise to a northwest‐southeast tilted band of rainfall anomalies. However, the composite diagrams of several atmospheric fields associated with northward propagation like vorticity, low‐level convergence, and oceanic variables like sea surface temperature and mixed layer depth do not show this difference in propagation speed and all exhibit a speed of nearly 0.75°/day in both the ocean basins. The difference in speed of ISO‐filtered rainfall is explained through moisture flux convergence. Anomalous horizontal moisture advection plays a major role over AS in preconditioning the atmosphere and making it favorable for convection. Anomalous wind acting on climatological moisture gradient is the dominant term in the moisture advection equation. Easterly wind anomalies associated with a low‐level anticyclone over India helps advect moisture from the eastern side of the domain. The northwest‐southeast tilt of ISO is dictated by the atmospheric processes of moisture advection with the upper ocean playing a more passive role in causing the tilt.
Karmakar, N., & Misra, V. (2019). The Relation of Intraseasonal Variations With Local Onset and Demise of the Indian Summer Monsoon. J. Geophys. Res. Atmos. , 124 (5), 2483–2506.
Abstract: Two of the most important hydroclimatic features of the Indian Summer Monsoon (ISM) rainfall are its onset/demise and Intraseasonal Oscillations (ISOs) manifested by the active‐break cycles. In this study, we aim to understand the quantitative association between these two phenomena. An objective definition of local onset/demise of the ISM based on more than a century‐long India Meteorological Department (IMD) rain‐gauge observation is taken into consideration. Using multichannel singular spectrum analysis (MSSA) we isolate northward propagating low‐ (20–60 days; LF‐ISO) and northwestward propagating high‐ (10–20 days; HF‐ISO) frequency ISOs from the daily ISM rainfall. Our results suggest that a large number of local onset (59%) and demise (62%) events occur during positive developing phases and positive decaying phases of two ISOs, respectively, with phase‐locking between LF‐ISO and HF‐ISO being particularly important. Local onset is largely associated with favorable phases of ISOs across India except for LF‐ISO over eastern India and HF‐ISO over western Ghats and central India (CI). We find that local demise is more coherent with the ISO phases, especially with HF‐ISO across the domain. We performed a case study to understand large‐scale association with the onset of the ISM over CI. In 44 of total 58 cases (1948–2005), when CI onset occurred during favorable LF‐ISO or HF‐ISO phase, they are either linked with a northward propagation of convection from the equator in LF‐ISO timescale (28 cases) or westward propagating structures from the western Pacific in HF‐ISO timescale (27 cases).
Katsaros, K. B., Bentamy, A., Bourassa, M., Ebuchi, N., Gower, J., Liu, W. T., et al. (2011). Climate Data Issues from an Oceanographic Remote Sensing Perspective. In D. Tang (Ed.), Remote Sensing of the Changing Oceans (pp. 7–32). Berlin: Springer.
Keeling, T. B. (2009). Modified JMA ENSO Index and Its Improvements to ENSO Classification . Master's thesis, Florida State University, Tallahassee, FL.
Abstract: El Nino-Southern Oscillation (ENSO) is a widely known phenomenon that affects many areas including the southeast United States. Over the southeast U.S. the Japan Meteorological Agency (JMA) ENSO index was modified to establish better classifications. In order to properly understand the effects of ENSO on this location a new approach was needed. Spatial resolution was improved by utilization of the PRISM dataset. PRISM provided monthly precipitation and temperature data over the contiguous US at 4 km resolution. Temporal resolution was improved by disregarding the traditional JMA definition of an ENSO year. The new definition requires six consecutive months of 0.5°C anomalies or larger to be listed as an ENSO event. By utilization of this definition, the ENSO index was modified to a monthly index from a yearly index. Many ENSO events begin in the summer months and end before the preceding September, therefore, an adoption of a monthly index is justified. Although several of the effects vary widely over the domain, there are a few prevalent patterns of ENSO effects. During warm phase, from November-April, wet conditions are seen in the coastal areas. July and August are both dry. From fall to spring, Florida and the Atlantic Coast are basically dry, however; the Mississippi River Valley doesn't appear wet as previous studies have indicted. Patterns of temperatures across the southeast are less variable than the precipitation. Differences between the ModJMA and JMA can be seen in several months, especially during late spring and early autumn. This result is not surprising based on the rigid definition of the JMA index. An interesting result presented itself throughout the study. Individual tropical storms can be identified with the increased resolution PRISM data provides. A state by state breakdown of the ModJMA conclusions provides regional summaries. The ModJMA better classifies ENSO periods and leads to a more precise impact of ENSO over the southeast United States.
Kelly, D. L., Letson, D., Nelson, F., Nolan, D. S., & Solís, D. (2012). Evolution of subjective hurricane risk perceptions: A Bayesian approach. Journal of Economic Behavior & Organization , 81 (2), 644–663.
