Impact of the Atlantic Warm Pool on precipitation and temperature in Florida during North Atlantic cold spells (original) (raw)
Related papers
Climate Response to Anomalously Large and Small Atlantic Warm Pools during the Summer
Journal of Climate, 2008
This paper uses the NCAR Community Atmospheric Model to show the influence of Atlantic warm pool (AWP) variability on the summer climate and Atlantic hurricane activity. The model runs show that the climate response to the AWP's heating extends beyond the AWP region to other regions such as the eastern North Pacific. Both the sea level pressure and precipitation display a significant response of low (high) pressure and increased (decreased) rainfall to an anomalously large (small) AWP, in areas with two centers located in the western tropical North Atlantic and in the eastern North Pacific. The rainfall response suggests that an anomalously large (small) AWP suppresses (enhances) the midsummer drought, a phenomenon with a diminution in rainfall during July and August in the region around Central America. In response to the pressure changes, the easterly Caribbean low-level jet is weakened (strengthened), as is its westward moisture transport. An anomalously large (small) AWP weakens (strengthens) the southerly Great Plains low-level jet, which results in reduced (enhanced) northward moisture transport from the Gulf of Mexico to the United States east of the Rocky Mountains and thus decreases (increases) the summer rainfall over the central United States, in agreement with observations. An anomalously large (small) AWP also reduces (enhances) the tropospheric vertical wind shear in the main hurricane development region and increases (decreases) the moist static instability of the troposphere, both of which favor (disfavor) the intensification of tropical storms into major hurricanes. Since the climate response to the North Atlantic SST anomalies is primarily forced at low latitudes, this study implies that reduced (enhanced) rainfall over North America and increased (decreased) hurricane activity due to the warm (cool) phase of the Atlantic multidecadal oscillation may be partly due to the AWP-induced changes of the northward moisture transport and the vertical wind shear and moist static instability associated with more frequent large (small) summer warm pools.
The oceanic influence on the rainy season of Peninsular Florida
Journal of Geophysical Research: Atmospheres, 2016
In this study we show that the robust surface ocean currents around Peninsular Florida, namely, the Loop and the Florida Currents, affect the terrestrial wet season of Peninsular Florida. We show this through two novel regional coupled ocean-atmosphere models with different bathymetries that dislocate and modulate the strength of these currents and thereby affect the overlying sea surface temperature (SST) and upper ocean heat content. This study show that a weaker current system produces colder coastal SSTs along the Atlantic coast of Florida that reduces the length of the wet season and the total seasonal accumulation of precipitation over Peninsular Florida relative to the regional climate model simulation, in which these currents are stronger. The moisture budget reveals that as a result of these forced changes to the temperature of the upper coastal Atlantic Ocean, overlying surface evaporation and atmospheric convection is modulated. This consequently changes the moisture flux convergence leading to the modulation of the terrestrial wet season rainfall over Peninsular Florida that manifests in changes in the length and distribution of daily rain rate of the wet season. The results of this study have implications on interpreting future changes to hydroclimate of Peninsular Florida owing to climate change and low-frequency changes to the Atlantic meridional overturning circulation that comprises the Loop and the Florida Currents as part of its upper branch. MISRA AND MISHRA RAINY SEASON OF PENINSULAR FLORIDA
Characterizing the rainy season of Peninsular Florida
Climate Dynamics, 2017
Peninsular Florida (PF) has a very distinct wet season that can be objectively defined with onset and demise dates based on daily rainfall. The dramatic onset of rains and its retreat coincides with the seasonal cycle of the regional scale atmospheric and upper ocean circulations and upper ocean heat content of the immediate surrounding ocean. The gradual warming of the Intra-Americas Seas (IAS; includes Gulf of Mexico, Caribbean Sea and parts of northwestern subtropical Atlantic Ocean) with the seasonal evolution of the Loop Current and increased atmospheric heat flux in to the ocean eventually enhance the moisture flux into terrestrial PF around the time of the onset of the Rainy Season of PF (RSPF). Similarly, the RSPF retreats with the cooling of the IAS that coincides with the weakening of the Loop Current and reduction of the upper ocean heat content of the IAS. It is also shown that anomalous onset and demise dates of the RSPF have implications on its seasonal rainfall anomalies.
Inhomogeneous influence of the Atlantic warm pool on United States precipitation
On interannual time scales, the warming of the Atlantic warm pool (AWP) is associated with a tripole sea surface temperature (SST) pattern in the North Atlantic and leads to more rainfall in the central and eastern US. On decadal-to-multidecadal time scales, the AWP warming corresponds to a basin-wide warming pattern and results in less precipitation in the central and eastern US. The inhomogeneous relationship between the AWP warming and US rainfall on different time scales is largely due to the sign of mid-latitude SST anomaly. The negative mid-latitude SST anomaly associated with the tripole pattern may enhance the low sea level pressure over the northeastern North American continent and also enhance the barotropic response there of the AWP-induced barotropic Rossby wave. This strengthened low pressure system, which is not exhibited when the warming is basin-wide, results in a different moisture transport variation and thus the rainfall pattern over the United States.
Journal of Hydrometeorology, 2021
In this study we examine the thermodynamically and dynamically forced hydroclimatic changes in the four representative seasons over Peninsular Florida (PF) from an unprecedented pair of high-resolution regional coupled ocean–atmosphere model simulations conducted at 10-km grid spacing for both the atmospheric and the oceanic components forced by one of the global climate models that participated in CMIP5. The model simulation verifies reasonably well with the observations and captures the distinct seasonal cycle of the region. The projected change in the freshwater flux in the mid-twenty-first century (2041–60) relative to the late twentieth century (1986–2005) shows a precipitation deficit in the summer over PF, which is statistically significant. This projected change in freshwater flux over PF is enabled by the strengthening of the anticyclonic North Atlantic subtropical high circulation with corresponding changes in divergence of moisture, advection of moisture from changes in t...
Impact of the Atlantic Warm Pool on the Summer Climate of the Western Hemisphere
Journal of Climate, 2007
The Atlantic warm pool (AWP) is a large body of warm water that comprises the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic. Located to its northeastern side is the North Atlantic subtropical high (NASH), which produces the tropical easterly trade winds. The easterly trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea, where the flow intensifies, forming the Caribbean low-level jet (CLLJ). The CLLJ then splits into two branches: one turning northward and connecting with the Great Plains low-level jet (GPLLJ), and the other continuing westward across Central America into the eastern North Pacific. The easterly CLLJ and its westward moisture transport are maximized in the summer and winter, whereas they are minimized in the fall and spring. This semiannual feature results from the semiannual variation of sea level pressure in the Caribbean region owing to the westward extension and eastward retreat of the NASH.
Journal of Climate, 2011
This study investigates the changes of the North Atlantic subtropical high (NASH) and its impact on summer precipitation over the southeastern (SE) United States using the 850-hPa geopotential height field in the National Centers for Environmental Prediction (NCEP) reanalysis, the 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40), long-term rainfall data, and Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) model simulations during the past six decades . The results show that the NASH in the last 30 yr has become more intense, and its western ridge has displaced westward with an enhanced meridional movement compared to the previous 30 yr. When the NASH moved closer to the continental United States in the three most recent decades, the effect of the NASH on the interannual variation of SE U.S. precipitation is enhanced through the ridge's north-south movement. The study's attribution analysis suggested that the changes of the NASH are mainly due to anthropogenic warming. In the twenty-first century with an increase of the atmospheric CO 2 concentration, the center of the NASH would be intensified and the western ridge of the NASH would shift farther westward. These changes would increase the likelihood of both strong anomalously wet and dry summers over the SE United States in the future, as suggested by the IPCC AR4 models.
2005
Little is known about the paleo-precipitation of the Florida Peninsula. In order to better understand Florida's late Holocene climate variability (last 4,200 years), the isotopic composition was analyzed of four speleothems from two caves, in west-central Florida. Two speleothems were collected from BRC Cave in Hernando County, and two others from Briar Cave in Marion County. This study represents the first speleothem-based paleoclimate records for Florida. Uranium-series disequilibrium analyses were determined by using thermal ionization mass spectrometry (TIMS) to provide accurate determination of chronology of the deposition of the speleothems. Stable isotopic analyses of oxygen and carbon were performed using stable isotope mass spectrometry, which provided information regarding changing amounts of precipitation (increase in precipitation, decrease in the δ 18 Oc) and types of vegetation above the cave (increased forest density, decrease in the δ 13 Cc). Variations in the speleothems δ 18 O composition reveal abrupt changes in precipitation amount, fluctuations that appear both regional and hemispheric in nature. Strong similarities between the speleothem δ 18 O, Lake Tulane δD record (Cross et al. vii 2003; 2004) and the SE US tree-ring record (surrogate for spring precipitation-Stahle and Cleaveland 1992) suggests a regional atmospheric influence on Florida's precipitation. The major causes of changes in precipitation are proposed to be Atlantic Multi-decadal Oscillation (AMO), El Niño and changes in the relative positions of the Intertropical Convergence Zone (ITCZ)-North Atlantic High (NAH). Comparison between the δ 18 Oc and surrogates of these influences, show all three have some effect. AMO and El Niño have short-term (decadal) influence and ITCZ-NAH has a long term (centennial) influence. The contributions of these climatic effects have implications for teleconnections involving Florida's climate; the AMO correlation shows higher latitude influence, while El Niño and the ITCZ show tropical influence on subtropical Florida.
Terrestrial and Ocean Climate of the 20th Century
Florida’s Climate: Changes, Variations, & Impacts, 2017
The Florida peninsula, with its close proximity to the equator surrounded by robust surface and deep water ocean currents, has a unique climate. Generally, its climate is mild with variations on numerous time scales, punctuated by periodic extreme weather events. In this chapter, we review the mechanisms by which some well-known natural variations impact the regional climate and modulate the occurrence of extreme weather over Florida and its neighboring oceans. In addition, we explore the role of land cover and land use changes on the regional climate over the same area. It is made apparent from the review that remote variations of climate have an equally important impact on the regional climate of Florida as the local changes to land cover and land use. Key Messages • Florida is a unique region to the east of the Rocky Mountains with a very distinct monsoonal type of wet season in the summer that distinguishes it from the rest of the seasons. • Florida's climate is as much affected by remote climate variations as local variability over land and its neighboring water bodies. Florida's climate is affected by more global scale natural variations like ENSO, AMO, PDO. Similarly, there is a discernible impact of local land cover and land use change on surface temperatures in Florida. • There are important interactions of the observed climate across time and spatial scales to consider. For example, the sea breeze over the Florida Panhandle is shown to be affected by the subtle variations of the Bermuda High. Similarly, ENSO forcing on Florida's winter climate is affected by decadal variations such as the PDO and the AMO.