Is the Atlantic Multidecadal oscillation real?
Is the Atlantic Multidecadal oscillation real?
The Atlantic Multi-decadal Oscillation (AMO) has been identified as a coherent mode of natural variability occurring in the North Atlantic Ocean with an estimated period of 60-80 years. It is based upon the average anomalies of sea surface temperatures (SST) in the North Atlantic basin, typically over 0-80N.
What causes Atlantic Multidecadal oscillation?
The extratropical anomalies are caused by the Rossby wave response to the tropical heating anomalies shown in Fig. 8.14. The low pressure centers at around 40° latitude at 150°W in each hemisphere drive cooling of the ocean surface there, mostly during the winter season.
What is the Atlantic meridional oscillation AMO and how does it influence the numbers of Atlantic hurricanes?
The AMO has affected air temperatures and rainfall over much of the Northern Hemisphere, in particular, North America and Europe. It is associated with changes in the frequency of North American droughts and is reflected in the frequency of severe Atlantic hurricanes.
What is multidecadal variability?
The Atlantic Multidecadal Oscillation (AMO), also known as Atlantic Multidecadal Variability (AMV), is the theorized variability of the sea surface temperature (SST) of the North Atlantic Ocean on the timescale of several decades.
How do you calculate AMO index?
The detrended Atlantic Multidecadal Oscillation (AMO) index, calculated by taking the annual mean global sea surface temperature (SST) anomaly when excluding the North Atlantic (0 •-60 • N, 75 • W-7.5 • W) and subtracting it from the annual mean SST anomaly averaged over the North Atlantic only.
What is the Atlantic Meridional Mode?
The Atlantic Meridional Mode is defined as the leading mode of non-ENSO coupled ocean / atmosphere variability in the Atlantic basin. The covariance matrix is decomposed via Singular Value Decomposition, and the leading statistical mode form the AMM SST and Wind patterns.
What is PDO climate?
The Pacific decadal oscillation (PDO) is a robust, recurring pattern of ocean-atmosphere climate variability centered over the mid-latitude Pacific basin. This climate pattern also affects coastal sea and continental surface air temperatures from Alaska to California.
How does PDO affect climate?
Is the Pacific in a cold or warm phase?
In the ‘warm’ or ‘positive’ phase, the west Pacific Ocean becomes cool and the wedge in the east warms. A ‘cool’ phase occurred from 1947 to 1976 (29 years), and a ‘warm’ phase from 1977 to 1999 (22 years).
What is the difference between the warm and cold phases of PDO?
The Pacific Decadal Oscillation (PDO) is a long-term ocean fluctuation of the Pacific Ocean. In the ‘warm’ or ‘positive’ phase, the west Pacific Ocean becomes cool and the wedge in the east warms. A ‘cool’ phase occurred from 1947 to 1976 (29 years), and a ‘warm’ phase from 1977 to 1999 (22 years).
Which oscillation has a strong influence on Atlantic hurricane frequency and strength?
Another prominent climate factor to influence Atlantic hurricane activity is the Atlantic Multi-Decadal Oscillation (AMO) (Goldenberg et al. 2001, Bell and Chelliah 2006). The warm phase of the AMO is associated with high-activity eras for Atlantic hurricanes, such as has been in place since 1995.
Does La Niña mean more rain?
Globally, La Niña often brings heavy rainfall to Indonesia, the Philippines, northern Australia and southern Africa. During La Niña, waters off the Pacific coast are colder and contain more nutrients than usual.
What is the name of the Atlantic Multidecadal Oscillation?
The Atlantic Multidecadal Oscillation ( AMO ), also known as Atlantic Multidecadal Variability ( AMV ), is the theorized variability of the sea surface temperature (SST) of the North Atlantic Ocean on the timescale of several decades.
How is the AO related to the North Atlantic Oscillation?
The AO has decadal to centennial variability, and is closely related to the North Atlantic Oscillation (Section S15.2). AO variability affects the winds, so variations in the ocean circulation and ice drift in the Arctic and northern North Atlantic are closely tied to the AO.
How is the AMO related to the Pacific decadal oscillation?
Zhang and Delworth (2007) found that the AMO can contribute to the Pacific Decadal Oscillation (PDO) and the associated Pacific/North America (PNA) pattern at the multidecadal time scale, and suggested that a North Pacific regime shift (opposite to the 1976–77 shift) might occur several years after the mid 90’s shift in the observed AMO.
How are multidecadal variations of tropical North Atlantic SST related?
Multidecadal variations of observed tropical North Atlantic (TNA) SST are strongly anti-correlated with those of the observed TNA subsurface ocean temperature, with long-term trends removed. Therefore, the observed detrended multidecadal TNA subsurface temperature anomaly may be taken as a proxy for the past AMOC variability.
