An integrated data-model study of interactions between tropical monsoons and extra-tropical climate variability and extremes (INTEGRATE)

Lead Research Organisation: University of East Anglia
Department Name: Environmental Sciences

Abstract

In order to predict the evolution of inter-regional linkages this century, it is crucial to understand how they have evolved in the past. This is particularly important because extremes such as drought are modulated by decadal variability. Our study is motivated by recent identification of multidecadal links between 2000-year reconstructions of Tibetan Plateau precipitation and Northern Hemisphere temperature. We will go far beyond this initial finding by combining insights gained from coupled climate models and observations (instrumental, tree-ring and documentary records) to identify large-scale modes that link the variability of tropical monsoons and northern extratropical climates on multiple timescales. We will (i) better understand the teleconnections between monsoon and extratropical regions (with particular emphasis on the Arctic), (ii) evaluate the ability of climate models to reproduce observed behaviour including regional extremes, (iii) explore mechanisms that drive the observed behaviour and understand how the linkages may evolve under future climate change using simulations with a hierarchy of models. Paleoclimate records, including temperature-sensitive tree-ring records from the Eurasian Arctic and precipitation-sensitive series from the Asian monsoon regions provide a unique opportunity to identify associations on annual to multidecadal timescales. CMIP5 and CMIP6 "control" and "last millennium" runs will be used to assess simulated unforced variability and response to forcings such as volcanoes and to consider sea surface temperature and atmospheric circulation patterns associated with periods of extremes in the monsoon, extratropical and Arctic regions. New simulations with imposed anomalies (e.g. sea or land surface temperatures in particular regions) in conjunction with external forcing will be designed to explore the roles of basin-wide changes or land-surface interactions in generating and synchronising decadal variability. Implications for future climate change will be considered using model simulations and our improved understanding of mechanisms.

Planned Impact

The INTEGRATE project will deliver new understanding necessary to support better climate services by improving our understanding of the teleconnections that link regional climates in the Asian monsoon regions with the mid and high latitudes of the Northern Hemisphere. These interactions modulate climate variability and alter the risk of climate/weather extremes on timescales from years to multiple decades. In doing so, they will alter our expectations of climatic behaviour in these regions, such that the frequency of extremes or the relationship between the monsoon circulations and ENSO may vary on decadal and longer timescales. Providers of climate services (whether they are providing information regarding climatological conditions, frequency of weather extremes, seasonal forecasts or near-term climate projections) and potential users of these services thus cannot rely solely on recent experience and data for their decisions. Analysis of longer-term instrumental data, supplemented by the context provided by palaeoclimate reconstructions (with appropriate caution regarding their greater uncertainty), is clearly beneficial. Furthermore, services and decisions that are based upon climate model simulations will be on a sounder footing following additional evaluation of the ability of climate models to simulate observed behaviour, including the linkages between extra-tropical, Arctic and monsoon regions.

Publications

10 25 50
 
Description Understanding of natural climate variability

The Atlantic Multidecadal Oscillation (AMO) is one of the most important modes of natural climate variability in the ocean-atmosphere system. Our new reconstruction is the best estimate of how this natural climate mode has varied over the last millennium. It is a significant advance over previously published estimates because it used only circum-Atlantic proxies to obtain an estimate that is independent of variability in other oceans and because we addressed directly the role of external forcings on this region.

Our work has provided a timeseries of the AMO variability that will be used widely within the science community to assess how other regions of the world are influenced by the AMO (i.e. inter-region climatic linkages). Our paper has already been cited 108 times, indicating that it has begun to influence the science community.

The author team bought together experts in tree-ring data, climate dynamics and climate modelling. Without this combination, the work wouldn't have been published in such a high- impact journal because the editor and reviewers required all these components to be part of the published paper.
Exploitation Route The 1200-yr long timeseries that we estimated for Atlantic Multidecadal Variability and for Atlantic Multidecadal Oscillation is freely available in the World Data Centre for Paleoclimatology. It can be utilised and analysed to inform the ongoing debate about the existence of the AMV/AMO as a distinct timescale of variability or as an occasional volcanically forcing episode (see e.g. http://www.realclimate.org/index.php/archives/2021/03/the-rise-and-fall-of-the-atlantic-multidecadal-oscillation/).
Sectors Environment

URL https://www.ncdc.noaa.gov/paleo-search/study/22031
 
Title CRU TS3.24.01 
Description An update to the widely-used Climatic Research Unit high-resolution land climate dataset. This provides monthly gridded fields of temperature, precipitation, vapour pressure and cloud cover, interpolated from observations to a regular grid with resolution 0.5 degrees of latitude and longitude. This update provides data from 1901 to 2009, and is available from the British Atmospheric Data Centre. This update was supported by NCAS and by the INTEGRATE project. Citable as: University of East Anglia Climatic Research Unit; Harris, I.C.; Jones, P.D. (2017): CRU TS3.24.01: Climatic Research Unit (CRU) Time-Series (TS) Version 3.24.01 of High Resolution Gridded Data of Month-by-month Variation in Climate (Jan. 1901- Dec. 2015). Centre for Environmental Data Analysis, date of citation. http://catalogue.ceda.ac.uk/uuid/3df7562727314bab963282e6a0284f24 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
Impact n/a 
URL http://catalogue.ceda.ac.uk/uuid/3df7562727314bab963282e6a0284f24
 
Title Self-calibrating Palmer Drought Severity Index (scPDSI) 1901-2017 
Description The scPDSI metric was introduced by Wells et al. (2004), who give detailed information about its calculation. The scPDSI is a variant on the original PDSI of Palmer (1965), with the aim to make results from different climate regimes more comparable. As with the PDSI, the scPDSI is calculated from time series of precipitation and temperature, together with fixed parameters related to the soil/surface characteristics at each location. We calculated the scPDSI values using as input the interpolated fields of monthly precipitation and temperature observations available in the CRU high-resolution surface climate data set. The global land scPDSI on the same 0.5° grid (van der Schrier et al., 2013), calculated using a preliminary version of the CRU TS 3.23 high-resolution monthly climate data set (Harris et al., 2014). These have then been updated each year using newer versions of CRU TS input data, currently to the end of 2017 using a preliminary version of CRU TS 3.26. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact Our creation of this dataset has enabled our contribution to the annual "State of the Climate Report" published in the Bulletin of the American Meteorological Society. 
URL https://crudata.uea.ac.uk/cru/data/drought/
 
Title Self-calibrating Palmer Drought Severity Index (scPDSI) 1901-2018 
Description The scPDSI metric was introduced by Wells et al. (2004), who give detailed information about its calculation. The scPDSI is a variant on the original PDSI of Palmer (1965), with the aim to make results from different climate regimes more comparable. As with the PDSI, the scPDSI is calculated from time series of precipitation and temperature, together with fixed parameters related to the soil/surface characteristics at each location. We calculated the scPDSI values using as input the interpolated fields of monthly precipitation and temperature observations available in the CRU high-resolution surface climate data set. The global land scPDSI on the same 0.5° grid (van der Schrier et al., 2013), calculated using a preliminary version of the CRU TS 3.23 high-resolution monthly climate data set (Harris et al., 2014). These have then been updated each year using newer versions of CRU TS input data, currently to the end of 2018 using a preliminary version of CRU TS 4.03. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Our creation of this dataset has enabled our contribution to the annual "State of the Climate Report" published in the Bulletin of the American Meteorological Society. 
URL https://crudata.uea.ac.uk/cru/data/drought/
 
Description Workshop for practitioners (Royal Met Soc / NCAS conference, Manchester) 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact To what extent are 'research-grade' climate change tools and techniques meeting the needs of climate service providers? Within the climate change community there is an emerging juxtaposition of researchers dedicated to refinement of climate modelling and those that are focussed on decision making under uncertainty. Between the two are practitioners who are typically faced by tight deadlines, limited budgets, insufficient data and high expectations of clients/customers. Drs Geoff Darch and Jo Parker will open with practitioners' perspectives. Professors Rob Wilby and Tim Osborn will respond with technical options offered by researchers. Delegates will then have an opportunity to discuss solutions to different risk assessment and adaptation challenges raised by practitioners. Through this dialogue we will identify requirements that are not being met by existing 'research-grade' tools. This workshop will help set out an agenda of work for the research and practitioner communities. It will also highlight in which areas there is scope for greater involvement of practitioners in the co-production and application of this new knowledge.
Year(s) Of Engagement Activity 2016
URL https://www.rmets.org/sites/default/files/P5%20-To%20what%20extent%20are%20%e2%80%98research-grade%e...
 
Description Youtube video 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A video highlighting some of the key outcomes of the INTEGRATE project, for use by the Belmont Forum.
Year(s) Of Engagement Activity 2020
URL https://youtu.be/7Naw_-X3i9I