scholarly journals Hurricane annual cycle controlled by both seeds and genesis probability

2021 ◽  
Vol 118 (41) ◽  
pp. e2108397118
Author(s):  
Wenchang Yang ◽  
Tsung-Lin Hsieh ◽  
Gabriel A. Vecchi
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Annual Cycle ◽  
Climate Models ◽  
Essential Elements ◽  
Abrupt Increase ◽  
Annual Cycles ◽  
The North ◽  
Concise Representation ◽  
The North Atlantic

Understanding tropical cyclone (TC) climatology is a problem of profound societal significance and deep scientific interest. The annual cycle is the biggest radiatively forced signal in TC variability, presenting a key test of our understanding and modeling of TC activity. TCs over the North Atlantic (NA) basin, which are usually called hurricanes, have a sharp peak in the annual cycle, with more than half concentrated in only 3 mo (August to October), yet existing theories of TC genesis often predict a much smoother cycle. Here we apply a framework originally developed to study TC response to climate change in which TC genesis is determined by both the number of pre-TC synoptic disturbances (TC “seeds”) and the probability of TC genesis from the seeds. The combination of seeds and probability predicts a more consistent hurricane annual cycle, reproducing the compact season, as well as the abrupt increase from July to August in the NA across observations and climate models. The seeds-probability TC genesis framework also successfully captures TC annual cycles in different basins. The concise representation of the climate sensitivity of TCs from the annual cycle to climate change indicates that the framework captures the essential elements of the TC climate connection.

scholarly journals Are the Transient and Equilibrium Climate Change Patterns Similar in Response to Increased CO2?

2020 ◽  
Vol 33 (18) ◽  
pp. 8003-8023
Author(s):  
Danqing Huang ◽  
Aiguo Dai ◽  
Jian Zhu
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Climate Models ◽  
Surface Air Temperature ◽  
The Arctic ◽  
The North ◽  
Temperature And Precipitation ◽  
Time Periods ◽  
The North Atlantic ◽  
Subtropical Oceans

AbstractAfter a CO2 increase, whether the early transient and final equilibrium climate change patterns are similar has major implications. Here, we analyze long-term simulations from multiple climate models under increased CO2, together with the extended simulations from CMIP5, to compare the transient and equilibrium climate change patterns under different forcing scenarios. Results show that the normalized warming patterns (per 1 K of global warming) are broadly similar among different forcing scenarios (including abrupt 2 × CO2, 4 × CO2, and 1% CO2 increase per year) and during different time periods, except for the first 50 years or so when warming is weaker over the North Atlantic and Southern Ocean but stronger over most continents. During the first 200 years, this consistency is stronger over land than over ocean, but is lower in midlatitudes than other regions. Normalized precipitation change patterns are also similar, albeit to a lesser degree, among different forcing scenarios and across different time periods, although noticeable differences exist during the first few hundred years with smaller increases over the tropical Pacific. Precipitation over many subtropical oceans and land areas decreases consistently under different forcing scenarios and over all time periods. In particular, the transient and near-equilibrium change patterns for both surface air temperature and precipitation are similar over most of the globe, except for the North Atlantic warming hole, which is mainly a transient feature. The Arctic amplification and land–ocean warming contrast are largest during the first 100–200 years after CO2 quadrupling but they still exist in the equilibrium response.

scholarly journals Tropical cyclones and climate change: Recent results and uncertainties

2020 ◽  
Author(s):  
Suzana Camargo ◽  
Chia-Ying Lee ◽  
Adam Sobel ◽  
Michael Tippett
Keyword(s):  
Climate Change ◽  
Tropical Cyclones ◽  
North Atlantic ◽  
Climate Models ◽  
Dynamical Downscaling ◽  
Current Knowledge ◽  
Historical Period ◽  
The North ◽  
The North Atlantic ◽  
High Resolution Models

<p>Here I will describe recent results on the influence of climate change on tropical cyclones (TC) using the Columbia Hazard (CHAZ) model. Using environmental conditions from reanalysis and climate models and a statistical-dynamical downscaling methodology (Lee et al. 2018), CHAZ generates synthetic TCs that can be used to analyze TC risk.  I will first discuss the current knowledge and uncertainties in TC frequency projections. Then I will present our recent projections on TC frequency using CHAZ. Focusing on the North Atlantic, I will finish by discussing how we can use a combination of observations, high-resolution models and CHAZ synthetic TCs in the historical period to inform the reliability of the models' TC frequency projections. </p><p>Reference:</p><p>Lee, C.-Y., M.K. Tippett, A.H. Sobel, and S.J. Camargo, 2018. An environmentally forced tropical cyclone hazard model. J. Adv. Model. Earth Sys., 10, doi: 10.1002/2017MS001186.</p>

Potential Changes of the North Atlantic Wind and Wave Climate and Occurrence of Rogue Waves

2016 ◽  
Author(s):  
Elzbieta M. Bitner-Gregersen
Keyword(s):  
Climate Change ◽  
21St Century ◽  
North Atlantic ◽  
Radiative Forcing ◽  
Climate Models ◽  
Rogue Waves ◽  
The Past ◽  
The North ◽  
The North Atlantic ◽  
Wave Conditions

The present study investigates potential changes of wind and wave conditions in one North Atlantic location in the 21st century. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) uses four scenarios for future greenhouse gas concentrations in the atmosphere called Representative Concentration Pathways (RCP). Two of these scenarios with radiative forcing of 4.5 and 8.5 W/m2 by the end of the 21st century have been selected to project wind and wave conditions in the North Atlantic. The third generation (3G) wave model WAM, forced by winds obtained from GFDL-CM3, EC-Earth, HADGEM2, IPS-CM5A-MR, MRI-GCGCM3 and MIROC5 climate models, has been used to project waves for these two scenarios for the historical period 1971–2000 and the future period 2071–2100. Long-term probabilistic description of wind and waves is provided and deviations between the past and future wind and wave conditions are demonstrated, given attention to the projections obtained by use of the GFDL-CM3 and EC-Earth climate models. Changes in extreme wind and waves are shown and uncertainties associated with climate change projections discussed. Occurrence of rogue-prone crossing sea states which may trigger generation of rogue waves in the past and future climate is also investigated.

scholarly journals On the Interpretation of the North Atlantic Averaged Sea Surface Temperature

2020 ◽  
Vol 33 (14) ◽  
pp. 6025-6045
Author(s):  
Jing Sun ◽  
Mojib Latif ◽  
Wonsun Park ◽  
Taewook Park
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Climate Models ◽  
Ocean Dynamics ◽  
Sea Surface ◽  
The North ◽  
Sst Variability ◽  
The North Atlantic ◽  
Different Time Scales

AbstractThe North Atlantic (NA) basin-averaged sea surface temperature (NASST) is often used as an index to study climate variability in the NA sector. However, there is still some debate on what drives it. Based on observations and climate models, an analysis of the different influences on the NASST index and its low-pass filtered version, the Atlantic multidecadal oscillation (AMO) index, is provided. In particular, the relationships of the two indices with some of its mechanistic drivers including the Atlantic meridional overturning circulation (AMOC) are investigated. In observations, the NASST index accounts for significant SST variability over the tropical and subpolar NA. The NASST index is shown to lump together SST variability originating from different mechanisms operating on different time scales. The AMO index emphasizes the subpolar SST variability. In the climate models, the SST-anomaly pattern associated with the NASST index is similar. The AMO index, however, only represents pronounced SST variability over the extratropical NA, and this variability is significantly linked to the AMOC. There is a sensitivity of this linkage to the cold NA SST bias observed in many climate models. Models suffering from a large cold bias exhibit a relatively weak linkage between the AMOC and AMO and vice versa. Finally, the basin-averaged SST in its unfiltered form, which has been used to question a strong influence of ocean dynamics on NA SST variability, mixes together multiple types of variability occurring on different time scales and therefore underemphasizes the role of ocean dynamics in the multidecadal variability of NA SSTs.

scholarly journals Ocean Warming Effect on Surface Gravity Wave Climate Change for the End of the Twenty-First Century

2013 ◽  
Vol 26 (16) ◽  
pp. 6046-6066 ◽  
Author(s):  
Yalin Fan ◽  
Isaac M. Held ◽  
Shian-Jiann Lin ◽  
Xiaolan L. Wang
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Austral Summer ◽  
South Pacific ◽  
First Century ◽  
The South ◽  
Coupled Models ◽  
The North ◽  
The North Atlantic ◽  
Twenty First Century

Abstract Surface wind (U10) and significant wave height (Hs) response to global warming are investigated using a coupled atmosphere–wave model by perturbing the sea surface temperatures (SSTs) with anomalies generated by the Working Group on Coupled Modeling (WGCM) phase 3 of the Coupled Model Intercomparison Project (CMIP3) coupled models that use the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4)/Special Report on Emissions Scenarios A1B (SRES A1B) scenario late in the twenty-first century. Several consistent changes were observed across all four realizations for the seasonal means: robust increase of U10 and Hs in the Southern Ocean for both the austral summer and winter due to the poleward shift of the jet stream; a dipole pattern of the U10 and Hs with increases in the northeast sector and decreases at the midlatitude during boreal winter in the North Atlantic due to the more frequent occurrence of the positive phases of the North Atlantic Oscillation (NAO); and strong decrease of U10 and Hs in the tropical western Pacific Ocean during austral summer, which might be caused by the joint effect of the weakening of the Walker circulation and the large hurricane frequency decrease in the South Pacific. Changes of the 99th percentile U10 and Hs are twice as strong as changes in the seasonal means, and the maximum changes are mainly dominated by the changes in hurricanes. Robust strong decreases of U10 and Hs in the South Pacific are obtained because of the large hurricane frequency decrease, while the results in the Northern Hemisphere basins differ among the models. An additional sensitivity experiment suggests that the qualitative response of U10 and Hs is not affected by using SST anomalies only and maintaining the radiative forcing unchanged (using 1980 values), as in this study.

scholarly journals The role of local sea surface temperature pattern changes in shaping climate change in the North Atlantic sector

2018 ◽  
Vol 52 (1-2) ◽  
pp. 417-438 ◽  
Author(s):  
Ralf Hand ◽  
Noel S. Keenlyside ◽  
Nour-Eddine Omrani ◽  
Jürgen Bader ◽  
Richard J. Greatbatch
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Sea Surface ◽  
Temperature Pattern ◽  
Atlantic Sector ◽  
The North ◽  
The North Atlantic

scholarly journals Predictability of the Atlantic Overturning Circulation and Associated Surface Patterns in Two CCSM3 Climate Change Ensemble Experiments

2011 ◽  
Vol 24 (23) ◽  
pp. 6054-6076 ◽  
Author(s):  
Haiyan Teng ◽  
Grant Branstator ◽  
Gerald A. Meehl
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Meridional Overturning Circulation ◽  
Subpolar Gyre ◽  
Overturning Circulation ◽  
The North ◽  
Surface Patterns ◽  
The Mean ◽  
The North Atlantic ◽  
Sst Anomalies

Abstract Predictability of the Atlantic meridional overturning circulation (AMOC) and associated oceanic and atmospheric fields on decadal time scales in the Community Climate System Model, version 3 (CCSM3) at T42 resolution is quantified with a 700-yr control run and two 40-member “perfect model” climate change experiments. After taking into account both the mean and spread about the mean of the forecast distributions and allowing for the possibility of time-evolving modes, the natural variability of the AMOC is found to be predictable for about a decade; beyond that range the forced predictability resulting from greenhouse gas forcing becomes dominant. The upper 500-m temperature in the North Atlantic is even more predictable than the AMOC by several years. This predictability is associated with subsurface and sea surface temperature (SST) anomalies that propagate in an anticlockwise direction along the subpolar gyre and tend to be prominent during the 10 yr following peaks in the amplitude of AMOC anomalies. Predictability in the North Atlantic SST mainly resides in the ensemble mean signals after three to four forecast years. Analysis suggests that in the CCSM3 the subpolar gyre SST anomalies associated with the AMOC variability can influence the atmosphere and produce surface climate predictability that goes beyond the ENSO time scale. However, the resulting initial-value predictability in the atmosphere is very weak.

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