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Decadal Climate Variability

Decadal Climate Variability

Vikram Mehta

ISBN: 978-1-119-10240-3

Jul 2020, American Geophysical Union

352 pages

Select type: O-Book


It is becoming increasingly important to understand and predict decadal climate variability, both because of its direct societal impacts and because shorter time scale weather and climate phenomena, such as heavy rainfall events and tropical cyclones, vary at decadal time scale. With chapters on the North Pacific Oscillation, the Modulation of Tropical cyclones, and the Chaotic Dynamics of the Tropical Coupled Ocean-atmosphere System, this book is the first to study the topic in-depth, providing a comprehensive review of the field to graduate students, and post-doctoral and other scientists.
1. Contents list:.

1. Introduction.

Importance of climate variability and change to society, and decadal climate variability’s historic influence on society; the rationale and organization of the book.

Phenomena (Based on instrument observations and paleoclimate proxies).

2. Association between Variability in Solar and Lunar Influences and the Earth’s Climate.

History of the quest to find solar and lunar influences on climate and to use them for climate prediction; a contemporary look at the possible physics of how solar and lunar influences can influence the stratosphere, the troposphere, and the upper ocean.

3. The North Atlantic Oscillation and The Conveyor Belt.

The Conveyor Belt or the thermohaline circulation (THC) transports heat and salt (or freshwater) in the Atlantic from lower latitudes to high, northern latitudes and, in the process, makes Europe livable. The Arctic Ocean circulation and sea ice also play an important role in the thermohaline circulation. Decadal variability of the THC and the North Atlantic Oscillation (NAO) have been associated with decadal variability of European climate, Atlantic sea-surface temperatures, and frequency of intense Atlantic hurricanes. The THC and NAO phenomena, their decadal variability, and their influence on land climate will be described..

4. The Tropical Atlantic Dipole: Mystery or Myth?.

Decadal variability of a bipolar sea-surface temperature pattern in the Atlantic, straddling the equator, has been known for a long time to modulate rainfall in northeast Brazil and west Africa. Starting with the history of research on this association, attempts during the last ten years to gain insight into this phenomenon will be described to answer the question posed in the chapter title..

5. The North Pacific Oscillation.

The North Pacific Oscillation, along with the Southern Oscillation and the North Atlantic Oscillation, was found by Sir Gilbert Walker in the late 1920s-early 1930s. It has gained prominence in the last ten years as a possible major component of decadal variability of the North Pacific ocean-atmosphere system, with impacts on North American climate. This, possibly coupled, ocean-atmosphere phenomenon will be described in this chapter..

6. The Tropical Warm Pools.

Surface temperatures in the tropical eastern Indian, western Pacific, and western Atlantic Oceans are usually warmer than 28°C and are, therefore, the major source of heat for driving the global atmosphere. Small changes in the warm surface temperature can have nonlinearly large impacts on atmospheric convection, therefore small-amplitude decadal variability of the Warm Pool temperatures influences not only tropical climate but also the global climate. Moreover, decadal variability of the Warm Pool temperatures is shown to influence the ENSO phenomenon and tropical cyclone frequency. The research so far in this emerging area of decadal variability research will be reviewed in this chapter..

7. The Southern Oceans.

Although observations in and over the Southern Oceans are sparse and their time series are not as long as in the Northern Hemisphere, some patterns of decadal variability in and over the Southern Oceans are emerging. These patterns will be described in this chapter..

8. The Climate Variability on Land.

Because precipitation and surface air temperature observations on land go back many decades to many centuries, there is a long history of analysis of decadal climate variability on land in many parts of the world. This research and attempts to associate decadal land climate variability with decadal variability phenomena in/over the oceans will be reviewed in this chapter..

9. The Bursts in El Niño-Southern Oscillation.

The El Niño-Southern Oscillation phenomenon and its predictability are known to vary at decadal time scale. The research on these “bursts” of El Niño-La Niña events will be reviewed..

10. The Modulation of Tropical Cyclones.

Decadal variability of ocean-atmosphere conditions in the tropical Pacific and Atlantic has been associated with variability in tropical cyclone frequency. This association will be described in this chapter..

Theories (Based on analytical and numerical models).

11. The Variability of External Influences on the Earth’s Climate.

Many mechanisms of variability of solar, lunar, and volcanic forcings causing decadal climate variability have been proposed. These mechanisms and evidence for and against them will be described in this chapter..

12. The Oceans’ Inertia.

Generation of decadal climate variability due to the integration of atmospheric high-frequency forcings by the high-inertia oceans was proposed as a hypothesis over 25 years ago. This hypothesis and its extensions will be reviewed..

13. The Effects of Wind, Heat, and Water on the The Conveyor Belt.

Ocean-atmosphere interactions in the North Atlantic via momentum, heat, and freshwater fluxes can cause decadal variability of the thermohaline circulation. The voluminous published literature on this topic will be reviewed in this chapter..

14. The Tropical-subtropical Meridional Oceanic Circulations.

Wind-driven and thermohaline circulations in the tropics-subtropics have strong components in the latitude-depth plane and can cause decadal variability in circulation and temperature because of the slow time scales of circulations in the latitude-depth plane. Such variability can interact with the atmosphere and cause decadal climate variability. The hypothesized mechanisms will be described in this chapter..

15. The Chaotic Dynamics of the Tropical Coupled Ocean-atmosphere System.

Models of the coupled, equatorial ocean-atmosphere system have produced decadal variability of ENSO ever since such models came into existence. These model results have inspired development of theories of decadal variability of ENSO caused by nonlinear dynamics of the equatorial coupled system. These theories will be reviewed in this chapter..

16. The Effects of Waves, Earth Rotation, and Land Boundaries.

Oceanic Rossby and Kelvin waves, undergoing multiple reflections between land boundaries in the Pacific, have formed the backbone of ENSO theories. Now, such waves, especially Rossby waves in the tropics and subtropics, are being invoked as important mechanisms of free and/or solar variability-forced modes of decadal variability. Such waves are also important in ocean gyre adjustments to changes in forcings, leading to decadal variability. This chapter will contain a review of these theories..

Predictability and Prediction.

17. Empirical and Dynamical Predictability.

Although very little research has been done on potential climate predictability beyond a few years’ lead time, the research on empirical and dynamical predictability at multiyear to decadal time scales to date will be reviewed in this chapter..

Societal Impacts.

18. Water Resources, Agriculture, Forestry, and Fisheries.

Historical records of decadal precipitation, stream flow, and droughts/floods, and the resultant impacts on agriculture in many parts of the world will be reviewed. The documented influences of the decadal variability phenomena described in previous chapters on water resources, agriculture, forests, and fisheries will also be reviewed..

19. Hurricanes, Typhoons, and other Extreme Weather Events.

Continuing from Chapter 10, this chapter will review societal impacts of tropical cyclones and other extreme weather events..

20. Health.

Pertinent peer-reviewed papers and reports published by the World Health Organization will be summarized in this chapter..

21. Outstanding Problems and Possible Solutions.

Outstanding questions to fill gaps in our knowledge, including how to identify and quantify anthropogenic climate change in the presence of natural decadal climate variability; the problems in addressing the questions; and possible solutions, including observing system requirements and model development; will be addressed in this chapter..