The sensitivity of ECHAM4/ML to a double CO2 scenario for the Late Miocene and the comparison to terrestrial proxy data

Steppuhn, Anke; Micheels, A.; Bruch, Angela A; Uhl, Dieter; Utescher, Torsten; Mosbrugger, Volker

doi:10.1016/j.gloplacha.2006.09.003

Cited by 43 publications

(52 citation statements)

References 58 publications

(135 reference statements)

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“…This is mainly associated with the changes in the planetary scale westerly flow rather than the regional scale surface pressure gradient between the Asian continent and the North Pacific, which is weakened in both TORT and GTORT (see MO in Table 3) and would actually favour a weaker E-Asian winter monsoon wind. The importance of the westerlies in maintaining a strong winter monsoon wind in both GTORT and TORT agrees with the studies by Ding et al (1999) and Sun (2004), which emphasize the relevance of westerlies for dust . For the present-day classification, the temperature fields are derived from CRU TS 2.1 data set (Mitchell and Jones, 2005).…”

Section: Winter Monsoonsupporting

confidence: 90%

“…The ocean circulation model MPIOM uses an Arakawa C-grid with an approximate resolution of 3 • × 3 • and the vertical domain is represented by 40 unevenly spaced levels. The setup design of GTORT is largely based on studies for the Late Miocene using the model version ECHAM4 coupled to a slab ocean model (Steppuhn et al, 2006(Steppuhn et al, , 2007Micheels et al, 2007) (see also Table 1). Atmospheric CO 2 of GTORT is 360 ppm, which is the same as in GCTRL but also feasible for the Late Miocene (e.g.…”

Section: Initial and Lateral Boundary Forcingmentioning

confidence: 99%

“…Dutton and Barron, 1997;Steppuhn et al, 2006Steppuhn et al, , 2007Micheels et al, 2007Micheels et al, , 2011Lunt et al, 2008). However, all these experiments use coarse spatial resolution, thus lack regional details over the Asian monsoon area.…”

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confidence: 99%

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Regional climate model experiments to investigate the Asian monsoon in the Late Miocene

2011

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Abstract. The Late Miocene (11.6-5.3 Ma) is a crucial period in the history of the Asian monsoon. Significant changes in the Asian climate regime have been documented for this period, which saw the formation of the modern Asian monsoon system. However, the spatiotemporal structure of these changes is still ambiguous, and the associated mechanisms are debated. Here, we present a simulation of the average state of the Asian monsoon climate for the Tortonian (11-7 Ma) using the regional climate model CCLM3.2. We employ relatively high spatial resolution (1 • × 1 • ) and adapt the physical boundary conditions such as topography, land-sea distribution and vegetation in the regional model to represent the Late Miocene. As climatological forcing, the output of a Tortonian run with a fully-coupled atmosphere-ocean general circulation model is used. Our regional Tortonian run shows a stronger-than-present East Asian winter monsoon wind as a result of the enhanced mid-latitude westerly wind of our global forcing and the lowered present-day northern Tibetan Plateau in the regional model. The summer monsoon circulation is generally weakened in our regional Tortonian run compared to today. However, the changes of summer monsoon precipitation exhibit major regional differences. Precipitation decreases in northern China and northern India, but increases in southern China, the western coast and the southern tip of India. This can be attributed to the changes in both the regional topography (e.g. the lower northern Tibetan Plateau) and the global climate conditions (e.g. the higher sea surface temperature). The spread of dry summer conditions over northern China and northern Pakistan in our Tortonian run further implies that the monsoonal climate may not have been Correspondence to: H. Tang (hui.tang@helsinki.fi) fully established in these regions in the Tortonian. Compared with the global model, the high resolution regional model highlights the spatial differences of the Asian monsoon climate in the Tortonian, and better characterizes the convective activity and its response to regional topographical changes. It therefore provides a useful and compared to global models, a complementary tool to improve our understanding of the Asian monsoon evolution in the Late Miocene.

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Section: Winter Monsoonsupporting

confidence: 90%

Section: Initial and Lateral Boundary Forcingmentioning

confidence: 99%

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Regional climate model experiments to investigate the Asian monsoon in the Late Miocene

2011

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“…This agrees with the proxy record in Alaska, Iceland, Siberia (Steppuhn et al 2007), Europe (Mosbrugger et al 2005;Bruch et al 2004Bruch et al , 2006, Asia (Bruch and Gabrielyan 2002;Xu et al 2008;Wang et al 2001) and North America (Axelrod and Bailey 1969;Baghai and Jorstad 1995). Nevertheless, the vegetation-induced temperature decline in the high-and mid-latitudes is weaker than found in the proxy record (Steppuhn et al 2007) and represents only one piece of the Cenozoic cooling puzzle. However, the strong connection between the lower and higher northern latitudes is supported by Micheels et al (2009).…”

Section: Discussionsupporting

confidence: 84%

Climate impact of high northern vegetation: Late Miocene and present

Schneck

Micheels

Mosbrugger

2011

Int J Earth Sci (Geol Rundsch)

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“…al., 2004;You et al, 2009) and close to modern values in the late Miocene (Steppuhn et al, 2007), but spatial coverage is lacking especially in the eastern equatorial Pacific (EEP). Also, terrestrial temperatures in the mid-latitudes are recorded as warmer than modern in the early and middle Miocene (Wolfe, 1994;Uhl et al, 2006;Micheels et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

Goldner¹,

Huber²,

Diffenbaugh

et al. 2011

Clim. Past

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Abstract. Substantial evidence exists for wetter-thanmodern continental conditions in North America during the pre-Quaternary warm climate intervals. This is in apparent conflict with the robust global prediction for future climate change of a northward expansion of the subtropical dry zones that should drive aridification of many semiarid regions. Indeed, areas of expected future aridification include much of western North America, where extensive paleoenvironmental records are documented to have been much wetter before the onset of Quaternary ice ages. It has also been proposed that climates previous to the Quaternary may have been characterized as being in a state with warmer-than-modern eastern equatorial sea surface temperatures (SSTs). Because equatorial Pacific SSTs exert strong controls on midlatitude atmospheric circulation and the global hydrologic cycle, the teleconnected response from this permanent El Niño-like mean state has been proposed as a useful analogue model, or "blueprint", for understanding global climatological anomalies in the past. The present study quantitatively explores the implications of this blueprint for past climates with a specific focus on the Miocene and Pliocene, using a global climate model (CAM3.0) and a nested high-resolution climate model (RegCM3) to study the hydrologic impacts on global and North American climate of a change in mean SSTs resembling that which occurs during modern El Niño events. We find that the global circulation response to a permanent El Niño resembles a large, long El Niño event. This state also exhibits equatorial super-rotation, which would represent a fundamental change to the tropical circulations. We also find a southward shift in winter storm tracks in the Pacific and Atlantic, which affects precipitation and temperature over the mid-latitudes. In addition, summertime precipitation increases over the majority of the continental UnitedCorrespondence to: A. Goldner (agoldner@purdue.edu)States. These increases in precipitation are controlled by shifts in the subtropical jet and secondary atmospheric feedbacks. Based on these results and the data proxy comparison, we conclude that a permanent El Niño like state is one potential explanation of wetter-than-modern conditions observed in paleoclimate-proxy records, particularly over the western United States.

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The sensitivity of ECHAM4/ML to a double CO2 scenario for the Late Miocene and the comparison to terrestrial proxy data

Cited by 43 publications

References 58 publications

Regional climate model experiments to investigate the Asian monsoon in the Late Miocene

Regional climate model experiments to investigate the Asian monsoon in the Late Miocene

Climate impact of high northern vegetation: Late Miocene and present

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

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The sensitivity of ECHAM4/ML to a double CO2 scenario for the Late Miocene and the comparison to terrestrial proxy data

Cited by 43 publications

References 58 publications

Regional climate model experiments to investigate the Asian monsoon in the Late Miocene

Regional climate model experiments to investigate the Asian monsoon in the Late Miocene

Climate impact of high northern vegetation: Late Miocene and present

Implications of the permanent El Niño teleconnection &quot;blueprint&quot; for past global and North American hydroclimatology

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Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology