James J. O’Brien

Florida State University | FSU · Center for Ocean-Atmospheric Prediction Studies (COAPS)

We welcome the comments of Landsea (2015, hereafter L15) and we1 applaud his efforts toward reanalyzing past tropical cyclone data in the Atlantic (Landsea et al. 2008, 2012, 2014; Hagen et al. 2012). However, L15 does not substantially change the conclusions stated in Kunkel et al. (2013, hereafter K13). L15 voices two main concerns: 1. The U.S. l...

Farmers need information about the climate that match their planning horizon (20 to 30 years), without the biases and problems associated with the climate model outputs. One source of climate information for such assessment can be obtained from historic climate record of surface observations. The analysis of the long-term temperature records of the...

The Florida Climate Consortium (FLC) 1 , whose goals are production and application of seasonal to inter-annual climate forecasts, include the Florida State University, the University of Florida, and the University of Miami. The FLC was formed in 1997, primarily with funding from NOAA. In 1999, the FLC shifted its focus from South America to the So...

Climate risks pose wicked problems, which are problems that do not have a set solution. Instead, both greater understanding of the wicked problem and partial solutions to the problem evolve iteratively. As such, the research paradigm for climate risk management demands that farmers and extension agents become collaborators with scientists. Opportun...

We integrate state-of-the-art climate projections, crop modeling systems and economic assessment to develop a tool for studying and assessing agricultural production in the southeast United States. This integrated framework will enable us to assess the potential impact of future climate variability and trend on the production of economically-valuab...

Values added by the NARCCAP regional climate models, compared to corresponding global climate models, are explicitly unveiled by using non-traditional skill evaluation statistics. The conventional model evaluation methods, such as temporal correlation of seasonal average rainfall, cannot explain the values of dynamically downscaled data. The hidden...

In this paper we examine the variations of the boreal summer season sea breeze circulation along the Florida panhandle coast from relatively high resolution (10 km) regional climate model integrations. The 23 year climatology (1979-2001) of the multidecadal dynamically downscaled simulations forced by the National Centers for Environmental Predicti...

This study investigates the characteristics of tides in the Gulf of Mexico (GoM) and the response to forcing by local tidal potential and tides propagating as waves through straits connecting this semienclosed sea to the Caribbean Sea and Atlantic Ocean. Numerical simulations performed with the Navy Coastal Ocean Model run in a barotropic configura...

This study focuses on modeling the tidal dynamics in the Gulf of Mexico (GoM). In particular, the study addresses the problem of differentiating the sources of tidal energy in this semi-enclosed sea. Tidal energy can enter the basin through propagation of tidal signals through the straits connecting the GoM to the Atlantic Ocean, or by local tidal...

This study assesses the regional-scale summer precipitation produced by the dynamical downscaling of analyzed large-scale fields. The main goal of this study is to investigate how much the regional model adds smaller scale precipitation information that the large-scale fields do not resolve. The modeling region for this study covers the southeaster...

Seasonally predicted precipitation at a resolution of 2.5° was statistically downscaled to a fine spatial scale of ~20km over the southeastern United States. The downscaling was conducted for spring and summer, when the fine-scale prediction of precipitation is typically very challenging in this region. We obtained the global model precipitation fo...

A comprehensive evaluation of crop yield simulations with various seasonal climate data is performed to improve the current practice of crop yield projections. The El Niño-Southern Oscillation (ENSO)-based historical data are commonly used to predict the upcoming season crop yields over the southeastern United States. In this study, eight different...

Changes in the peak wind gust magnitude in association with the warm and cold phases of the El Niño-Southern Oscillation (ENSO) are identified over the contiguous United States. All calculations of the peak wind gust are differences in the extreme phases of ENSO (warm and cold) relative to neutral for all stations in the study that pass the complet...

We developed methods of forecasting cotton (Gossypium birsutum L. var. birsutum) yields at a county level 3 mo before harvest for the states of Alabama and Georgia. Cotton yield historical records for 57 counties were obtained from NASS and detrended using a low-pass spectral filter. A Canonical Correlation Analysis regression-based model was annua...

Recent observations over the Sigsbee Escarpment in the Gulf of Mexico have revealed extremely energetic deep currents (near 1 m s-1), which are trapped along the escarpment. Both scientific interest and engineering needs demand dynamical understanding of these extreme events, and can benefit from a numerical model designed to complement observation...

A new method of assimilating sea surface height (SSH) data into ocean models is introduced and tested. Many features observable by satellite altimetry are approximated by the first baroclinic mode over much of the ocean, especially in the lower (but non-equatorial) and mid latitude regions. Based on this dynamical trait, a reduced-dynamics adjoint...

Although the amount of water contained in the soil seems insignificant when compared to the total amount of water on a global-scale, soil moisture is widely recognized as a crucial variable for climate studies. It plays a key role in regulating the interaction between the atmosphere and the land-surface by controlling the repartition between the su...

We present results from a 15-year 10-member warm season (March-September) hindcast ensemble of maximum and minimum surface air temperatures and precipitation in southeast USA. The hindcasts are derived from the Florida State University/Center for Ocean-Atmospheric Prediction Studies Global Spectral Model (FSU/COAPS GSM) and downscaled using both th...

Numerical model experiments have been performed to analyze the low-latitude baroclinic continental shelf response to a tropical cyclone. The theory of coastally trapped waves suggests that, provided appropriate slope, latitude, stratification and wind stress, bottom-intensified topographic Rossby waves can be generated by the storm. Based on a scal...

Air temperature anomalies over eastern North America and Europe are analysed during the extreme phases of the two leading low-frequency modes of North Atlantic sea surface temperature (SST) during the 1906–2005 period. The leading mode of SST is a multi-decadal signal—commonly referred to as the Atlantic multi-decadal oscillation—with uniform polar...

The mission of the Southeast Climate Consortium (SECC) is to provide climate information and decision support tools to help stakeholders manage risks arising from climate variability. While the SECC has pursued this mission with a focus on seasonal climate since 1998, in response to stakeholder interest we began developing climate change informatio...

Global/Regional Circulation Models (GCM/RCM) predict the interannual climate variability better than the absolute values of meteorological variables. Statistical bias-correction methods increase the quality of daily model predictions of incoming solar radiation, maximum and minimum temperatures and rainfall frequency and amount. However, when bias-...

Severe freezes impacting agriculture in Florida were associated with some major climate patterns, such as El Niño and Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO). In this study, we examined whether seasonal ensemble integrations of a regional model could capture the tendencies of freezes in the Florida peninsula during each ENS...

Time series filtering (e. g., smoothing) can be done in the spectral domain without loss of endpoints. However, filtering is commonly performed in the time domain using convolutions, resulting in lost points near the series endpoints. Multiple incarnations of a least squares minimization approach are developed that retain the endpoint intervals tha...

The purpose of this study is to quantify the cross-shelf transport of water masses and organic carbon at the Gulf of Tehuantepec and relate this to the physical processes in the area. A medium-complexity, nitrogen-based ecosystem model is developed in order to simulate the ecosystem in the northeast tropical Pacific. The ecosystem model is run “off...

Understanding rainfall variability in the arid, rugged landscapes of Iran requires studying the climatology and spatial patterns of daily precipitation. This paper applies geostatistical and other methods to daily precipitation data from 90 stations that are distributed across Iran to calculate daily rainfall concentration and intensity and map the...

The potential to predict cotton yields up to one month before planting in the southeastern United States is assessed in this research. To do this, regional atmospheric variables that are related to historic summer rainfall and cotton yields were identified. The use of simulations of those variables from a global circulation model (GCM) for estimati...

Coarsely resolved surface air temperature (2 m height) seasonal integrations from the Florida State University/Center for Ocean-Atmospheric Prediction Studies Global Spectral Model (FSU/COAPS GSM) (~1.8º lon.-lat. (T63)) for the period of 1994 to 2002 (March through September each year) are downscaled to a fine spatial scale of ~20 km. Dynamical an...

Less focus has been given to early stage of tropical cyclone formation referred to as genesis stage. Presently, a robust technique for locating and monitoring tropical disturbances from the early genesis stage to the tropical depression stage in the Atlantic basin. The approach used a combination of QuickSCAT observations of surface vorticity and G...

Ocean wind vectors from the SeaWinds scatterometer on QuikSCAT and GOES imagery are used to develop an objective technique that can detect and monitor tropical disturbances associated with the early stages of tropical cyclogenesis in the Atlantic basin. The technique is based on identification of surface vorticity and wind speed signatures that exc...

Short-term climate variations including the El Niño/Southern Oscillation (ENSO) cause anomalies in temperature and precipitation that could produce or contribute to extreme events including droughts and wildfires. Wildfire threat potential in the Southeast is based in part upon the Keetch–Byram Drought Index (KBDI), and the KBDI uses daily temperat...

Analyses of daily sea level data show the impacts of El Niño-Southern Oscillation (ENSO) in the Gulf of Mexico (GOM). Data from three stations (St. Petersburg, Florida, Pensacola, Florida, and Galveston, Texas), all of which have at least 50 years of daily observations, are processed to identify the interannual signals. Although low frequency (inte...

This study seeks to understand the spatial variability of monthly and daily rainfall in Alabama, Georgia, and Florida, USA. Monthly spatial statistics are needed to improve downscaling from climate models producing seasonal rainfall forecasts, and spatial correlation of daily rainfall is needed to inform spatial weather generators used in climate r...

The Sigsbee Escarpment in the northwestern Gulf of Mexico is a steep topographic feature found at depths between 1500m and 3000m depth, depending on location along the escarpment. Observations of intense (50- 100 cm/s) velocities near the ocean bottom over the escarpment have been linked with bottom-intensified Topographic Rossby Waves (TRWs). A mo...

Regional variations in North Atlantic hurricane landfall frequency along the U.S. coastline are examined in relation to the phase of El Niño-Southern Oscillation (ENSO). ENSO warm (cold) phases are known to reduce (increase) hurricane activity in the North Atlantic basin as a whole. Using best-track data from the U.S. National Hurricane Center, reg...

Research has shown strong relationship s between ENSO phase and climate in the southeastern USA during the boreal winter. Crop yields in this region are significantly affected by ENSO phase due to predictable patterns of climate during this time of the year. However, both climate during the boreal summer months and cotton yields in this region show...

The Southeast Climate Consortium was initiated in 2001 as a regional expansion of the Florida Consortium. The Florida Consortium of Universities (FLC), consisting of the University of Miami, the University of Florida, and Florida State University was formed in 1996 and was funded by the U.S. National Oceanic and Atmospheric Administration-Office of...

Propagation of barotropic topographic Rossby waves (TRWs) and Kelvin type waves over topography consisting of multiple steps is investigated. The transformation of the wave solution from one limiting case with narrow and small steps most closely approximating a continuous slope to another limiting case with wide and high steps is analyzed. The anal...

A coupled ocean and boundary layer flux numerical modeling system is used to study the upper ocean response to surface heat and momentum fluxes associated with a major hurricane, namely, Hurricane Dennis (July 2005) in the Gulf of Mexico. A suite of experiments is run using this modeling system, constructed by coupling a Navy Coastal Ocean Model si...

1] Numerical model experiments are conducted to address the previously unexplained anomalously high storm surge along the Florida coast of Apalachee Bay during Hurricane Dennis (2005). The 2 – 3 m surge observed during this storm cannot be obviously explained by the relatively weak local winds over this bay 275 km east of the storm center. Realisti...

Seasonal climate variability plays an important role in the production risks faced by producers. The majority of crop failures in the USA are associated with either a lack or excess of rainfall. Climate forecasts can be used to reduce risks faced by an agricultural enterprise, but simply providing better climate forecasts to potential users is not...

An 8-year database of sea surface temperature (SST), 7years of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) ocean color images, wind fields, and numerical model results are analyzed to identify regions and periods of coastal upwelling on the western and southern shelves of the Gulf of Mexico. On the seasonal scale, it is found that on the Tamaul...

TOPEX/Poseidon satellite altimeter observations and the Naval Research Laboratory Layered Ocean Model simulations show interannual variability in the number intensity of Tehuantepec eddies off the Mexican southwest coast. Analysis of the results illustrates that downwelling coastally trapped waves, which are generated in the equatorial Pacific, pla...

An advanced land model [the National Center for Atmospheric Research (NCAR) Community Land Model, version 2 (CLM2)] is coupled to the Florida State University (FSU) regional spectral model to improve seasonal surface climate outlooks at very high spatial and temporal resolution and to examine its potential for crop yield estimation. The regional mo...

In this research, sensitivity of LAI (Leaf Area Index) to modeled temperatures is investigated replacing prescribed monthly LAI in CLM2 (Community Land Model 2.0) with an LAI dataset derived from observation by MODIS (Moderate Resolution Imaging Spectroradiometer). The prescribed monthly LAI in CLM2 is based on NDVI data from AVHRR (Advanced Very H...

A new statistical downscaling method for the regionalization of global model simulations is developed in this study. The basis of this method is that clearer separation of prominent local climate signals (e.g., seasonal cycle, dominant intraseasonal or interannual oscillations) over the training period leads to better prediction of local climate sc...

A new objective technique is used to analyze monthly mean gridded fields of air and sea temperature, wind, specific humidity, sensible and latent heat flux, and wind stress over the Indian Ocean. A variational method produces a 1°x1° gridded product of surface turbulent fluxes and the variables needed to calculate these fluxes. The surface turbulen...

Analysis of observations of the Loop Current (LC) northward penetration and LC area, from satellite sea surface temperature, Topex/Poseidon (TP) sea surface height anomaly, and results from numerical simulations shows that when a relatively large cyclone remains north of the LC, the shedding period between two consecutive eddies may increase. It is...

We present a new weather generator, which simulates daily precipitation occurrence and daily maximum and minimum air temperature. Precipitation occurrence is simulated with a two-state, second-order Markov process, while maximum and minimum daily temperatures are simulated using spectral methods. Data generated at nine stations in the Southeastern...

Wind data from the SeaWinds instrument on NASA’s Quick Scatterometer (QuikSCAT) satellite are investigated to ascertain how well the surface manifestation of the Madden–Julian oscillation (MJO) can be resolved. The MJO signal is detected in nonfiltered gridded data using extended EOF analysis of the zonal wind field, overshadowed by annual, semiann...

A new method is described for forcing regional ocean models with wind stress fields derived from satellite scatterometer data. A variational technique is applied to produce regularly gridded surface wind (stress) fields in time and space using data from the NASA SeaWinds scatterometer aboard the QuikSCAT satellite. Three uniformly gridded wind stre...

A new objective time series of in situ-based monthly surface winds has been developed as a replacement for the subjective tropical Pacific Florida State University (FSU) winds. The new time series begins in January 1978, and it is ongoing. The objective method distinguishes between observations from volunteer observing ships (VOSs) and buoys, allow...

In the years 1999 and 2001, three intense tropical cyclones formed over the northern Indian Ocean—two over the Bay of Bengal during 15–19 and 25–29 October, 1999 and one over the Arabian Sea during 21–28 May, 2001. We examined the thermal, salinity and circulation responses at the sea surface due to these severe cyclones in order to understand the...

The current Florida State University (FSU) climate model is upgraded by coupling the National Center for Atmospheric Research (NCAR) Community Land Model Version 2 (CLM2) as its land component in order to make a better simulation of surface air temperature and precipitation on the seasonal time scale, which is important for crop model application....

Consecutive days of precipitation (precipitation runs) in the southeast U.S. are evaluated for spatial and temporal variations. A 55-year dataset of daily precipitation totals from selected stations across the study area is used to identify precipitation runs. Potential impacts from variations in consecutive days of precipitation on agricultural yi...

The seasonal variability of circulation on the continental shelves of the northern and western Gulf of Mexico is explained using observational data and a high-resolution numerical model. It is shown that the primarily wind driven circulation governs the salinity field on the shelves, by transporting low salinity water formed by river discharge alon...

The current Florida State University (FSU) global and regional climate models are upgraded by coupling the National Center for Atmospheric Research community land model (NCAR CLM2) as its land component in order to make a better simulation of land surface variables on the seasonal time scale which is important for crop model application. Climatolog...

Topographic Rossby waves (TRW) play an important role in the ocean dynamics in regions where the slope of the bottom topography is sufficiently large so as to dominate the beta-effect. TRW propagate signals in the ocean along the slopes over large distances [Oey and Lee, 2002]. Pacanowski and Gnanadesikan [1998] suggested that when the bottom slope...

The seasonal variability of circulation on the continental shelves of the northern and western Gulf of Mexico is explained using observational data and a high-resolution numerical model. It is shown that the primarily wind-driven circulation governs the salinity field on the shelves by transporting low-salinity water formed by river discharge along...

Observational studies have shown that in many regions of the World Ocean the eddy kinetic energy (EKE) significantly varies on interannual time scales. Comparing altimeter-derived EKE maps for 1993 and 1996, Stammer and Wunsch have mentioned a significant meridional redistribution of EKE in the North Atlantic Ocean and suggested the possible influe...

A nonlinear theory for the generation of the Ulleung Warm Eddy (UWE) is proposed. Using the nonlinear reduced gravity (shallow water) equations, it is shown analytically that the eddy is established in order to balance the northward momentum flux (i.e., the flow force) exerted by the separating western boundary current (WBC). In this scenario, the...

A new objective time series of in situ based monthly surface winds has been developed as a replacement for the subjective Tropical Pacific FSU winds. The new time series begins in Jan. 1978, and it is ongoing. The objective method distinguishes between observations from volunteer observing ships (VOS) and buoys, allowing different weights for these...

Algorithms are developed for the estimation of sea surface salinity (SSS) in the tropical Indian Ocean from the space-borne satellite measurements of outgoing longwave radiation (OLR). The algorithms are based on the interrelationships between OLR, the effective oceanic layer (EOL), climatological SSS (World Ocean Atlas 1998 (WOA98)), and freshwate...

Monthly and seasonal predictions of mean atmospheric states have traditionally been viewed as a boundary forcing problem, with little regard for the role of atmospheric initial conditions (IC). The potential predictability of these mean states is investigated using hindcasted monthly mean January (JAN) and seasonal mean January February March (JFM)...

Quality wind stress fields are desired for a wide range of oceanographic and atmospheric studies. An overview is presented of the monthly quick-look and research-quality tropical ocean wind (pseudostress) products produced for the Pacific and Indian Oceans by The Florida State University (FSU) and for the Atlantic Ocean by the French Institut de Re...

Observational studies based on altimeter data have shown that in many regions of the World Ocean the oceanic eddy kinetic energy (EKE) significantly varies on interannual timescales. Comparing altimeter-based EKE maps for 1993 and 1996, Stammer and Wunsch (1998) discuss a significant meridional redistribution of EKE in the North Atlantic and specul...

The seasonal circulation on the western shelf of the Gulf of Mexico is studied using a high-resolution numerical simulation, historical hydrographic data, sea level data, and satellite images. Three regions are distinguished, the Tamaulipas-Veracruz (TAVE) shelf, the Louisiana-Texas (LATEX) shelf, and the western Campeche Bank. On the TAVE shelf th...