Atmospheric circulation, hydroclimate change, and peat accumulation over the last 250 years inferred from a Sphagnum peatland in the southern Greater Khingan Mountains of Northeast China 

2021 ◽  
Author(s):  
Zuo Wang ◽  
Zicheng Yu
Keyword(s):  
Summer Monsoon ◽  
Yellow Sea ◽  
Northeast China ◽  
Carbon Accumulation ◽  
Western Pacific ◽  
The Yellow Sea ◽  
Accumulation Rates ◽  
Moisture Sources ◽  
Dry Conditions ◽  
The Western Pacific

<p>Northeast China—located near the northern limit of the influence by the East Asian summer monsoon—receives most moisture through the westerly airflow, but variations in moisture contributions from the Yellow Sea in the western Pacific Ocean determine its hydroclimate during summer monsoon season. The proportion of moisture from the Yellow Sea is strongly modulated by the location and intensity of the Western Pacific Subtropical High (WPSH). However, it is still unclear how sensitive regional hydroclimate to WPSH-modulated change in moisture sources and its impact on peatland carbon accumulation. Here, we used macrofossil data and paired δ<sup>13</sup>C and δ<sup>18</sup>O isotope analysis of Sphagnum moss cellulose from a well-dated bog from a steep mountain slope in the Greater Khingan Mountains (~47˚N) to reconstruct peatland moisture changes and elucidate past shifts in moisture sources. δ<sup>13</sup>C values reflect peatland surface moisture, as dry conditions with less water film effects would increase isotopic discrimination against <sup>13</sup>C and result in lower δ<sup>13</sup>C values. Our results from a 250-year peat record show a decrease of ~3‰ in δ<sup>13</sup>C from -25 to -28‰—with corresponding increase in dry-adapted moss Polytrichum—suggesting a drying trend since about 1980 AD. Also, the down-core δ<sup>18</sup>O and δ<sup>13</sup>C data show a positive correlation (r = 0.65, p < 0.001), in contrast with evaporative enrichment of δ<sup>18</sup>O being the dominant effect. We argue that δ<sup>18</sup>O values reflect the input of moisture derived from the Yellow Sea—that has higher δ<sup>18</sup>O values than that from the westerlies—as modulated by the WPSH. When the WPSH extends westward, it blocks moisture transport from the Yellow Sea to North China, causing low δ<sup>18</sup>O values in summer precipitation, dry conditions, and negative shifts in δ<sup>13</sup>C, and vice versa. Furthermore, carbon accumulation rates show a major decrease after the 1980s—despite that more recent peat tends to have higher apparent accumulation rates—suggesting a sensitive response of this steep-slope mountain peatland to shift in regional hydroclimate in monsoon-margin region of Northeast China.</p>

scholarly journals A new species of the genus Amphicteis Grube, 1850 (Annelida, Ampharetidae) from the Yellow Sea, China, together with a redescription of A. dalmatica Hutchings & Rainer, 1979

ZooKeys ◽  
2020 ◽  
Vol 988 ◽  
pp. 1-15
Author(s):  
Weina Wang ◽  
Jixing Sui ◽  
Xinzheng Li ◽  
Pat Hutchings ◽  
João Miguel de Matos Nogueira
Keyword(s):  
New Species ◽  
Yellow Sea ◽  
Western Pacific ◽  
The Yellow Sea ◽  
Australian Museum ◽  
Pacific Waters ◽  
A New Species

A new species of the ampharetid genus Amphicteis, A. hwanghaiensissp. nov., is described based on material from the Yellow Sea. The new species is characterized by the possession of long, stout, golden paleae with blunt tips, digitiform rudimentary notopodia on the abdominal uncinigers, uncini with a subrostral process, and a narrow rectangular hump separating branchial groups. Amphicteis dalmatica was redescribed from type materials at the Australian Museum, Sydney, and the differences between A. dalmatica and A. hwanghaiensissp. nov. are discussed. A key to distinguish Amphicteis species described or reported in Western Pacific waters is provided.

scholarly journals Summer Wind Effects on Coastal Upwelling in the Southwestern Yellow Sea

2021 ◽  
Vol 9 (9) ◽  
pp. 1021
Author(s):  
Bin Wang ◽  
Lei Wu ◽  
Ning Zhao ◽  
Tianran Liu ◽  
Naoki Hirose
Keyword(s):  
Summer Monsoon ◽  
Wind Stress ◽  
Yellow Sea ◽  
Coastal Upwelling ◽  
Circulation Model ◽  
Tidal Mixing ◽  
The Yellow Sea ◽  
Observation Data ◽  
Wind Stress Curl ◽  
Green Tides

The features of coastal upwelling in the southwestern Yellow Sea were investigated based on oceanology data from a research cruise and a regional circulation model. The observation data suggest that a relatively colder and saltier water core exists from the deeper layer to the surface, off the Subei Bank. The concentrations of nutrients also suggest that coastal upwelling is beneficial for nutrient enrichment in the upper layer. The numerical simulations are in good agreement with oceanology observations. Furthermore, sensitivity experiments indicate that, in addition to the tidal-induced upwelling and tidal mixing proposed in previous studies, the summer monsoon is also critical to vertical circulation in the southwestern Yellow Sea. The southwesterly wind stress and positive wind stress curl make considerable contributions to upwelling off the Subei coast compared with tidal motions. Moreover, this study also proposes that changes in the summer monsoon and its curl may have been helpful to the formation of upwelling during the past decade, which may have provided a favorable marine environment for the frequent occurrence of green tides. This study provides a theoretical basis for the mechanisms of coastal upwelling and the nitrogen cycle in the Yellow Sea.

Eastward Eddy Shedding of the Asian Summer Monsoon Anticyclone

2021 ◽  
Author(s):  
Xinyue Wang ◽  
William Randel ◽  
Yutian Wu
Keyword(s):  
North America ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Lower Troposphere ◽  
Western Pacific ◽  
The North ◽  
The Pacific ◽  
Asian Summer ◽  
The Western Pacific ◽  
Eddy Shedding

<p>Eastward eddy shedding of the Asian summer monsoon (ASM) anticyclone has a large impact on the chemical composition of the upper troposphere and lower stratosphere (UTLS) over the western Pacific. Here we investigate the dynamical mechanism of eastward eddy shedding in July and August using 41 years of the ERA5 6-hourly reanalysis data. We perform composite analyses of meteorological variables focusing on the eastward eddy shedding events with the presence of anticyclonic centers falling between 135<sup>•</sup>-140<sup>•</sup>E. The composited outgoing longwave radiation anomalies suggest enhanced convection near the Philippines Sea and the East China Sea one week beforehand. In the tropopause level, we see evident eastward propagating geopotential and meridional wind anomalies from the North Atlantic jet exit toward the western Pacific embedded along the extratropical westerly jet during day -10 to day 0. In the lower troposphere, we find that the geopotential anomalies aligned meridionally from the east Asian coast to the North Pacific to the northern North America during day -7 to day 0. The wave-activity flux is evaluated to identify the origin and propagation of the energy of the Rossby wave–like perturbation. In the UTLS we find a strong southeastward-pointing flux along 40<sup>•</sup>-50<sup>•</sup>N, resembling the Silk Road pattern. While in the lower troposphere, we also see a northeastward-pointing flux originating from tropical Philippine Sea across Japan to North America, resembling the Pacific-Japan pattern. Additional analysis is needed to study the relationship between the Silk Road pattern and the Pacific-Japan pattern.</p>

scholarly journals Impact of typhoons on the composition of the upper troposphere within the Asian summer monsoon anticyclone: the SWOP campaign in Lhasa 2013

2016 ◽  
Author(s):  
Dan Li ◽  
Bärbel Vogel ◽  
Jianchun Bian ◽  
Rolf Müller ◽  
Laura L. Pan ◽  
...  
Keyword(s):  
Water Vapour ◽  
Tropical Cyclones ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Vertical Transport ◽  
Western Pacific ◽  
Lagrangian Model ◽  
Upper Troposphere ◽  
Asian Summer ◽  
The Western Pacific

Abstract. In the frame of the SWOP (sounding water vapour, ozone, and particle) campaign during the Asian summer monsoon (ASM), ozone and water vapour profiles were measured by balloon-borne sensors launched from Lhasa (29.66° N, 91.14° E, elevation 3650 m), China, in August 2013. In total, 24 soundings were launched, nearly half of which show some strong variations in the relationship between ozone and water vapour in the tracer-tracer correlation in the upper troposphere and lower stratosphere (UTLS). 20-day backward trajectories of each sounding were calculated using the trajectory module of the Chemical Lagrangian Model of the Stratosphere (CLaMS) to analyse these variations. The trajectory calculations demonstrate that three tropical cyclones (tropical storm Jebi, typhoons Utor and Trami), which occurred over the Western Pacific Ocean during August 2013, had a considerable impact on the vertical distribution of ozone and water vapour by uplifting marine air masses to altitudes of the ASM anticyclone. Air parcels subsequently arrived at the observation site via two primary pathways: firstly via direct horizontal transport from the location of the typhoon to the station within approximately three days, and secondly via rotational subsidence, during which air parcels descend slowly along a circle following the anticyclone flow within a timescale of one week. Furthermore, the interplay between the spatial position of the ASM anticyclone and tropical cyclones plays a key role in controlling the transport pathways of air parcels from the boundary layer of the Western Pacific to Lhasa in horizontal as well as vertical transport. Moreover, the statistical analysis shows that the strongest impact by typhoons is found at altitudes between 14.5 km and 17 km (365–375 K). Low ozone values (50–80 ppbv) were observed between 370 K and 380 K due to the strong vertical transport within tropical cyclones.

Asian summer monsoon Chemical and Climate Impact Project (ACCLIP): Highlights of multi-model pre-mission study

2020 ◽  
Author(s):  
Doug Kinnison ◽  
Qing Liang ◽  
Laura Pan ◽  
Paul Newman ◽  
Elliot Atlas ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Wrf Model ◽  
Climate Impact ◽  
Western Pacific ◽  
Artificial Surface ◽  
Asian Summer ◽  
Transport Patterns ◽  
The Impact ◽  
The Western Pacific

<p>This presentation reports the findings of a multi-model pre-mission study in preparation for an airborne field campaign to investigate the upper troposphere and lower stratosphere (UTLS) composition under the influence of the Asian summer monsoon (ASM). The NSF/NASA supported airborne study is planned for the western Pacific atmosphere during July-August 2020 using a base in Okinawa, Japan. The pre-mission study uses three chemistry-transport models (i.e., NASA GSFC GEOS5, NCAR WACCM, and ECMWF CAMS) to investigate transport patterns and gas and aerosol chemical composition in the campaign region UTLS during the 2019 ASM period. In addition, artificial surface tracers from the WRF model helped identify the locations and evolution of rapid convective uplifting from regional sources. The impact of one typhoon occurrence during this 2019 ASM period will be discussed. Together, the multi-model results support the hypotheses of the ACCLIP campaign which identifies the western Pacific as a significant pathway for reactive chemical pollutants and climate relevant emissions from the ASM to enter the global UTLS.</p>

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