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  • Author or Editor: B. L. Li x
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Z. Q. Li
,
H. Xu
,
K. T. Li
,
D. H. Li
,
Y. S. Xie
,
L. Li
,
Y. Zhang
,
X. F. Gu
,
W. Zhao
,
Q. J. Tian
,
R. R. Deng
,
X. L. Su
,
B. Huang
,
Y. L. Qiao
,
W. Y. Cui
,
Y. Hu
,
C. L. Gong
,
Y. Q. Wang
,
X. F. Wang
,
J. P. Wang
,
W. B. Du
,
Z. Q. Pan
,
Z. Z. Li
, and
D. Bu

Abstract

An overview of Sun–Sky Radiometer Observation Network (SONET) measurements in China is presented. Based on observations at 16 distributed SONET sites in China, atmospheric aerosol parameters are acquired via standardization processes of operational measurement, maintenance, calibration, inversion, and quality control implemented since 2010. A climatology study is performed focusing on total columnar atmospheric aerosol characteristics, including optical (aerosol optical depth, ÅngstrÖm exponent, fine-mode fraction, single-scattering albedo), physical (volume particle size distribution), chemical composition (black carbon; brown carbon; fine-mode scattering component, coarse-mode component; and aerosol water), and radiative properties (aerosol radiative forcing and efficiency). Data analyses show that aerosol optical depth is low in the west but high in the east of China. Aerosol composition also shows significant spatial and temporal variations, leading to noticeable diversities in optical and physical property patterns. In west and north China, aerosols are generally affected by dust particles, while monsoon climate and human activities impose remarkable influences on aerosols in east and south China. Aerosols in China exhibit strong light-scattering capability and result in significant radiative cooling effects.

Full access
L. M. Beal
,
J. Vialard
,
M. K. Roxy
,
J. Li
,
M. Andres
,
H. Annamalai
,
M. Feng
,
W. Han
,
R. Hood
,
T. Lee
,
M. Lengaigne
,
R. Lumpkin
,
Y. Masumoto
,
M. J. McPhaden
,
M. Ravichandran
,
T. Shinoda
,
B. M. Sloyan
,
P. G. Strutton
,
A. C. Subramanian
,
T. Tozuka
,
C. C. Ummenhofer
,
A. S. Unnikrishnan
,
J. Wiggert
,
L. Yu
,
L. Cheng
,
D. G. Desbruyères
, and
V. Parvathi

Abstract

The Indian Ocean Observing System (IndOOS), established in 2006, is a multinational network of sustained oceanic measurements that underpin understanding and forecasting of weather and climate for the Indian Ocean region and beyond. Almost one-third of humanity lives around the Indian Ocean, many in countries dependent on fisheries and rain-fed agriculture that are vulnerable to climate variability and extremes. The Indian Ocean alone has absorbed a quarter of the global oceanic heat uptake over the last two decades and the fate of this heat and its impact on future change is unknown. Climate models project accelerating sea level rise, more frequent extremes in monsoon rainfall, and decreasing oceanic productivity. In view of these new scientific challenges, a 3-yr international review of the IndOOS by more than 60 scientific experts now highlights the need for an enhanced observing network that can better meet societal challenges, and provide more reliable forecasts. Here we present core findings from this review, including the need for 1) chemical, biological, and ecosystem measurements alongside physical parameters; 2) expansion into the western tropics to improve understanding of the monsoon circulation; 3) better-resolved upper ocean processes to improve understanding of air–sea coupling and yield better subseasonal to seasonal predictions; and 4) expansion into key coastal regions and the deep ocean to better constrain the basinwide energy budget. These goals will require new agreements and partnerships with and among Indian Ocean rim countries, creating opportunities for them to enhance their monitoring and forecasting capacity as part of IndOOS-2.

Free access
L. M. Beal
,
J. Vialard
,
M. K. Roxy
,
J. Li
,
M. Andres
,
H. Annamalai
,
M. Feng
,
W. Han
,
R. Hood
,
T. Lee
,
M. Lengaigne
,
R. Lumpkin
,
Y. Masumoto
,
M. J. McPhaden
,
M. Ravichandran
,
T. Shinoda
,
B. M. Sloyan
,
P. G. Strutton
,
A. C. Subramanian
,
T. Tozuka
,
C. C. Ummenhofer
,
A. S. Unnikrishnan
,
J. Wiggert
,
L. Yu
,
L. Cheng
,
D. G. Desbruyères
, and
V. Parvathi
Full access
B. W. Golding
,
S. P. Ballard
,
K. Mylne
,
N. Roberts
,
A. Saulter
,
C. Wilson
,
P. Agnew
,
L. S. Davis
,
J. Trice
,
C. Jones
,
D. Simonin
,
Z. Li
,
C. Pierce
,
A. Bennett
,
M. Weeks
, and
S. Moseley

The provision of weather forecasts for the London Olympic and Paralympic Games in 2012 offered the opportunity for the Met Office to accelerate the transition to operations of several advanced numerical modeling capabilities and to demonstrate their performance to external scientists. It was also an event that captured public interest, providing an opportunity to educate and build trust in the weather forecasting enterprise in the United Kingdom and beyond. The baseline NWP guidance for the duration of the Olympic Games came from three main configurations of the Met Office Unified Model: global 25-km deterministic, North Atlantic/Europe 18-km ensemble, and U.K. 1.5-km deterministic. The advanced capabilities demonstrated during the Olympic Games consisted of a rapid-update hourly cycle of a 1.5-km grid length configuration for the southern United Kingdom using four-dimensional variational data assimilation (4D-Var) and enhanced observations; a 2.2-km grid length U.K. ensemble; a 333-m grid length configuration of the Unified Model and 250-m configuration of the Simulating Waves Nearshore (SWAN) ocean wave model for Weymouth Bay; and a 12-km grid length configuration of Air Quality in the Unified Model with prognostic aerosols and chemistry. Despite their different levels of maturity, each of the new capabilities provided useful additional guidance to Met Office weather advisors, contributing to an outstanding service to the Olympic Games organizers and the public. The website provided layered access to information about the science and to selected real-time products, substantially raising the profile of Met Office weather forecasting research among the United Kingdom and overseas public.

Full access
S. Pawson
,
K. Kodera
,
K. Hamilton
,
T. G. Shepherd
,
S. R. Beagley
,
B. A. Boville
,
J. D. Farrara
,
T. D. A. Fairlie
,
A. Kitoh
,
W. A. Lahoz
,
U. Langematz
,
E. Manzini
,
D. H. Rind
,
A. A. Scaife
,
K. Shibata
,
P. Simon
,
R. Swinbank
,
L. Takacs
,
R. J. Wilson
,
J. A. Al-Saadi
,
M. Amodei
,
M. Chiba
,
L. Coy
,
J. de Grandpré
,
R. S. Eckman
,
M. Fiorino
,
W. L. Grose
,
H. Koide
,
J. N. Koshyk
,
D. Li
,
J. Lerner
,
J. D. Mahlman
,
N. A. McFarlane
,
C. R. Mechoso
,
A. Molod
,
A. O'Neill
,
R. B. Pierce
,
W. J. Randel
,
R. B. Rood
, and
F. Wu

To investigate the effects of the middle atmosphere on climate, the World Climate Research Programme is supporting the project “Stratospheric Processes and their Role in Climate” (SPARC). A central theme of SPARC, to examine model simulations of the coupled troposphere–middle atmosphere system, is being performed through the initiative called GRIPS (GCM-Reality Intercomparison Project for SPARC). In this paper, an overview of the objectives of GRIPS is given. Initial activities include an assessment of the performance of middle atmosphere climate models, and preliminary results from this evaluation are presented here. It is shown that although all 13 models evaluated represent most major features of the mean atmospheric state, there are deficiencies in the magnitude and location of the features, which cannot easily be traced to the formulation (resolution or the parameterizations included) of the models. Most models show a cold bias in all locations, apart from the tropical tropopause region where they can be either too warm or too cold. The strengths and locations of the major jets are often misrepresented in the models. Looking at three-dimensional fields reveals, for some models, more severe deficiencies in the magnitude and positioning of the dominant structures (such as the Aleutian high in the stratosphere), although undersampling might explain some of these differences from observations. All the models have shortcomings in their simulations of the present-day climate, which might limit the accuracy of predictions of the climate response to ozone change and other anomalous forcing.

Full access
S. Gualdi
,
S. Somot
,
L. Li
,
V. Artale
,
M. Adani
,
A. Bellucci
,
A. Braun
,
S. Calmanti
,
A. Carillo
,
A. Dell'Aquila
,
M. Déqué
,
C. Dubois
,
A. Elizalde
,
A. Harzallah
,
D. Jacob
,
B. L'Hévéder
,
W. May
,
P. Oddo
,
P. Ruti
,
A. Sanna
,
G. Sannino
,
E. Scoccimarro
,
F. Sevault
, and
A. Navarra

In this article, the authors describe an innovative multimodel system developed within the Climate Change and Impact Research: The Mediterranean Environment (CIRCE) European Union (EU) Sixth Framework Programme (FP6) project and used to produce simulations of the Mediterranean Sea regional climate. The models include high-resolution Mediterranean Sea components, which allow assessment of the role of the basin and in particular of the air–sea feedbacks in the climate of the region.

The models have been integrated from 1951 to 2050, using observed radiative forcings during the first half of the simulation period and the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario during the second half.

The projections show a substantial warming (about 1.5°–2°C) and a significant decrease of precipitation (about 5%) in the region for the scenario period. However, locally the changes might be even larger. In the same period, the projected surface net heat loss decreases, leading to a weaker cooling of the Mediterranean Sea by the atmosphere, whereas the water budget appears to increase, leading the basin to lose more water through its surface than in the past. Overall, these results are consistent with the findings of previous scenario simulations, such as the Prediction of Regional Scenarios and Uncertainties for Defining European Climate Change Risks and Effects (PRUDENCE), Ensemble-Based Predictions of Climate Changes and Their Impacts (ENSEMBLES), and phase 3 of the Coupled Model Intercomparison Project (CMIP3). The agreement suggests that these findings are robust to substantial changes in the configuration of the models used to make the simulations.

Finally, the models produce a 2021–50 mean steric sea level rise that ranges between +7 and +12 cm, with respect to the period of reference.

Full access
P. M. Ruti
,
S. Somot
,
F. Giorgi
,
C. Dubois
,
E. Flaounas
,
A. Obermann
,
A. Dell’Aquila
,
G. Pisacane
,
A. Harzallah
,
E. Lombardi
,
B. Ahrens
,
N. Akhtar
,
A. Alias
,
T. Arsouze
,
R. Aznar
,
S. Bastin
,
J. Bartholy
,
K. Béranger
,
J. Beuvier
,
S. Bouffies-Cloché
,
J. Brauch
,
W. Cabos
,
S. Calmanti
,
J.-C. Calvet
,
A. Carillo
,
D. Conte
,
E. Coppola
,
V. Djurdjevic
,
P. Drobinski
,
A. Elizalde-Arellano
,
M. Gaertner
,
P. Galàn
,
C. Gallardo
,
S. Gualdi
,
M. Goncalves
,
O. Jorba
,
G. Jordà
,
B. L’Heveder
,
C. Lebeaupin-Brossier
,
L. Li
,
G. Liguori
,
P. Lionello
,
D. Maciàs
,
P. Nabat
,
B. Önol
,
B. Raikovic
,
K. Ramage
,
F. Sevault
,
G. Sannino
,
M. V. Struglia
,
A. Sanna
,
C. Torma
, and
V. Vervatis

Abstract

The Mediterranean is expected to be one of the most prominent and vulnerable climate change “hotspots” of the twenty-first century, and the physical mechanisms underlying this finding are still not clear. Furthermore, complex interactions and feedbacks involving ocean–atmosphere–land–biogeochemical processes play a prominent role in modulating the climate and environment of the Mediterranean region on a range of spatial and temporal scales. Therefore, it is critical to provide robust climate change information for use in vulnerability–impact–adaptation assessment studies considering the Mediterranean as a fully coupled environmental system. The Mediterranean Coordinated Regional Downscaling Experiment (Med-CORDEX) initiative aims at coordinating the Mediterranean climate modeling community toward the development of fully coupled regional climate simulations, improving all relevant components of the system from atmosphere and ocean dynamics to land surface, hydrology, and biogeochemical processes. The primary goals of Med-CORDEX are to improve understanding of past climate variability and trends and to provide more accurate and reliable future projections, assessing in a quantitative and robust way the added value of using high-resolution and coupled regional climate models. The coordination activities and the scientific outcomes of Med-CORDEX can produce an important framework to foster the development of regional Earth system models in several key regions worldwide.

Full access
Britton B. Stephens
,
Matthew C. Long
,
Ralph F. Keeling
,
Eric A. Kort
,
Colm Sweeney
,
Eric C. Apel
,
Elliot L. Atlas
,
Stuart Beaton
,
Jonathan D. Bent
,
Nicola J. Blake
,
James F. Bresch
,
Joanna Casey
,
Bruce C. Daube
,
Minghui Diao
,
Ernesto Diaz
,
Heidi Dierssen
,
Valeria Donets
,
Bo-Cai Gao
,
Michelle Gierach
,
Robert Green
,
Justin Haag
,
Matthew Hayman
,
Alan J. Hills
,
Martín S. Hoecker-Martínez
,
Shawn B. Honomichl
,
Rebecca S. Hornbrook
,
Jorgen B. Jensen
,
Rong-Rong Li
,
Ian McCubbin
,
Kathryn McKain
,
Eric J. Morgan
,
Scott Nolte
,
Jordan G. Powers
,
Bryan Rainwater
,
Kaylan Randolph
,
Mike Reeves
,
Sue M. Schauffler
,
Katherine Smith
,
Mackenzie Smith
,
Jeff Stith
,
Gregory Stossmeister
,
Darin W. Toohey
, and
Andrew S. Watt

Abstract

The Southern Ocean plays a critical role in the global climate system by mediating atmosphere–ocean partitioning of heat and carbon dioxide. However, Earth system models are demonstrably deficient in the Southern Ocean, leading to large uncertainties in future air–sea CO2 flux projections under climate warming and incomplete interpretations of natural variability on interannual to geologic time scales. Here, we describe a recent aircraft observational campaign, the O2/N2 Ratio and CO2 Airborne Southern Ocean (ORCAS) study, which collected measurements over the Southern Ocean during January and February 2016. The primary research objective of the ORCAS campaign was to improve observational constraints on the seasonal exchange of atmospheric carbon dioxide and oxygen with the Southern Ocean. The campaign also included measurements of anthropogenic and marine biogenic reactive gases; high-resolution, hyperspectral ocean color imaging of the ocean surface; and microphysical data relevant for understanding and modeling cloud processes. In each of these components of the ORCAS project, the campaign has significantly expanded the amount of observational data available for this remote region. Ongoing research based on these observations will contribute to advancing our understanding of this climatically important system across a range of topics including carbon cycling, atmospheric chemistry and transport, and cloud physics. This article presents an overview of the scientific and methodological aspects of the ORCAS project and highlights early findings.

Full access
P. W. Thorne
,
R. J. Allan
,
L. Ashcroft
,
P. Brohan
,
R. J. H Dunn
,
M. J. Menne
,
P. R. Pearce
,
J. Picas
,
K. M. Willett
,
M. Benoy
,
S. Bronnimann
,
P. O. Canziani
,
J. Coll
,
R. Crouthamel
,
G. P. Compo
,
D. Cuppett
,
M. Curley
,
C. Duffy
,
I. Gillespie
,
J. Guijarro
,
S. Jourdain
,
E. C. Kent
,
H. Kubota
,
T. P. Legg
,
Q. Li
,
J. Matsumoto
,
C. Murphy
,
N. A. Rayner
,
J. J. Rennie
,
E. Rustemeier
,
L. C. Slivinski
,
V. Slonosky
,
A. Squintu
,
B. Tinz
,
M. A. Valente
,
S. Walsh
,
X. L. Wang
,
N. Westcott
,
K. Wood
,
S. D. Woodruff
, and
S. J. Worley

Abstract

Observations are the foundation for understanding the climate system. Yet, currently available land meteorological data are highly fractured into various global, regional, and national holdings for different variables and time scales, from a variety of sources, and in a mixture of formats. Added to this, many data are still inaccessible for analysis and usage. To meet modern scientific and societal demands as well as emerging needs such as the provision of climate services, it is essential that we improve the management and curation of available land-based meteorological holdings. We need a comprehensive global set of data holdings, of known provenance, that is truly integrated both across essential climate variables (ECVs) and across time scales to meet the broad range of stakeholder needs. These holdings must be easily discoverable, made available in accessible formats, and backed up by multitiered user support. The present paper provides a high-level overview, based upon broad community input, of the steps that are required to bring about this integration. The significant challenge is to find a sustained means to realize this vision. This requires a long-term international program. The database that results will transform our collective ability to provide societally relevant research, analysis, and predictions in many weather- and climate-related application areas across much of the globe.

Open access
G. Vaughan
,
J. Methven
,
D. Anderson
,
B. Antonescu
,
L. Baker
,
T. P. Baker
,
S. P. Ballard
,
K. N. Bower
,
P. R. A. Brown
,
J. Chagnon
,
T. W. Choularton
,
J. Chylik
,
P. J. Connolly
,
P. A. Cook
,
R. J. Cotton
,
J. Crosier
,
C. Dearden
,
J. R. Dorsey
,
T. H. A. Frame
,
M. W. Gallagher
,
M. Goodliff
,
S. L. Gray
,
B. J. Harvey
,
P. Knippertz
,
H. W. Lean
,
D. Li
,
G. Lloyd
,
O. Martínez–Alvarado
,
J. Nicol
,
J. Norris
,
E. Öström
,
J. Owen
,
D. J. Parker
,
R. S. Plant
,
I. A. Renfrew
,
N. M. Roberts
,
P. Rosenberg
,
A. C. Rudd
,
D. M. Schultz
,
J. P. Taylor
,
T. Trzeciak
,
R. Tubbs
,
A. K. Vance
,
P. J. van Leeuwen
,
A. Wellpott
, and
A. Woolley

Abstract

The Diabatic Influences on Mesoscale Structures in Extratropical Storms (DIAMET) project aims to improve forecasts of high-impact weather in extratropical cyclones through field measurements, high-resolution numerical modeling, and improved design of ensemble forecasting and data assimilation systems. This article introduces DIAMET and presents some of the first results. Four field campaigns were conducted by the project, one of which, in late 2011, coincided with an exceptionally stormy period marked by an unusually strong, zonal North Atlantic jet stream and a succession of severe windstorms in northwest Europe. As a result, December 2011 had the highest monthly North Atlantic Oscillation index (2.52) of any December in the last 60 years. Detailed observations of several of these storms were gathered using the U.K.’s BAe 146 research aircraft and extensive ground-based measurements. As an example of the results obtained during the campaign, observations are presented of Extratropical Cyclone Friedhelm on 8 December 2011, when surface winds with gusts exceeding 30 m s–1 crossed central Scotland, leading to widespread disruption to transportation and electricity supply. Friedhelm deepened 44 hPa in 24 h and developed a pronounced bent-back front wrapping around the storm center. The strongest winds at 850 hPa and the surface occurred in the southern quadrant of the storm, and detailed measurements showed these to be most intense in clear air between bands of showers. High-resolution ensemble forecasts from the Met Office showed similar features, with the strongest winds aligned in linear swaths between the bands, suggesting that there is potential for improved skill in forecasts of damaging winds.

Open access