A new perspective of the physical processes associated with the clear-sky greenhouse effect over high latitudes

2004 ◽  
Vol 21 (2) ◽  
pp. 171-180
Author(s):  
Cao Zuohao ◽  
Stewart Ronald E. ◽  
Yau M. K.
Keyword(s):  
Greenhouse Effect ◽  
High Latitudes ◽  
Physical Processes ◽  
Clear Sky ◽  
New Perspective

scholarly journals Model-dependence of the CO<sub>2</sub> threshold for melting the hard Snowball Earth

2011 ◽  
Vol 7 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Y. Hu ◽  
J. Yang ◽  
F. Ding ◽  
W. R. Peltier
Keyword(s):  
Surface Temperature ◽  
Greenhouse Effect ◽  
Surface Albedo ◽  
Snowball Earth ◽  
Pressure Broadening ◽  
Near Surface ◽  
Induced Absorption ◽  
Cloud Forcing ◽  
Clear Sky ◽  
Convective Model

Abstract. One of the critical issues of the Snowball Earth hypothesis is the CO2 threshold for triggering the deglaciation. Using Community Atmospheric Model version 3.0 (CAM3), we study the problem for the CO2 threshold. Our simulations show large differences from previous results (e.g. Pierrehumbert, 2004, 2005; Le Hir et al., 2007). At 0.2 bars of CO2, the January maximum near-surface temperature is about 268 K, about 13 K higher than that in Pierrehumbert (2004, 2005), but lower than the value of 270 K for 0.1 bar of CO2 in Le Hir et al. (2007). It is found that the difference of simulation results is mainly due to model sensitivity of greenhouse effect and longwave cloud forcing to increasing CO2. At 0.2 bars of CO2, CAM3 yields 117 Wm−2 of clear-sky greenhouse effect and 32 Wm−2 of longwave cloud forcing, versus only about 77 Wm−2 and 10.5 Wm−2 in Pierrehumbert (2004, 2005), respectively. CAM3 has comparable clear-sky greenhouse effect to that in Le Hir et al. (2007), but lower longwave cloud forcing. CAM3 also produces much stronger Hadley cells than that in Pierrehumbert (2005). Effects of pressure broadening and collision-induced absorption are also studied using a radiative-convective model and CAM3. Both effects substantially increase surface temperature and thus lower the CO2 threshold. The radiative-convective model yields a CO2 threshold of about 0.21 bars with surface albedo of 0.663. Without considering the effects of pressure broadening and collision-induced absorption, CAM3 yields an approximate CO2 threshold of about 1.0 bar for surface albedo of about 0.6. However, the threshold is lowered to 0.38 bars as both effects are considered.

scholarly journals Uncertainty of the CO<sub>2</sub> threshold for melting a hard Snowball Earth

2010 ◽  
Vol 6 (4) ◽  
pp. 1337-1350 ◽  
Author(s):  
Y. Hu ◽  
J. Yang
Keyword(s):  
Greenhouse Effect ◽  
Atmospheric Model ◽  
Snowball Earth ◽  
Near Surface ◽  
Cloud Forcing ◽  
Clear Sky ◽  
Critical Issues ◽  
Simulation Results ◽  
High Level ◽  
Hadley Cells

Abstract. One of the critical issues of the Snowball Earth hypothesis is how high level of CO2 is required for triggering the deglaciation. Using Community Atmospheric Model version 3 (CAM3), we study the problem for the CO2 threshold. Our simulations show large differences from previous results (Pierrehumbert, 2004, 2005). At 0.2 bars of CO2, the January maximum near-surface temperature is about 268 K, about 13 K higher than that in Pierrehumbert (2004, 2005), but lower than the value of 270 K for 0.1 bar of CO2 in Le Hir et al. (2007). It is found that the diversity of simulation results is mainly due to model sensitivity of greenhouse effect and longwave cloud forcing to increasing CO2. At 0.2 bar of CO2, CAM3 yields 117 Wm −2 of clear-sky greenhouse effect and 32 Wm−2 of longwave cloud forcing, versus only about 77 Wm−2 and 10.5 Wm−2 in Pierrehumbert (2004, 2005), respectively. CAM3 has comparable clear-sky greenhouse effect to that in Le Hir et al. (2007), but lower longwave cloud forcing. CAM3 also produces much stronger Hadley cells than in Pierrehumbert (2005).

scholarly journals Comparison of OMI NO<sub>2</sub> observations and their seasonal and weekly cycles with ground-based measurements in Helsinki

2016 ◽  
Author(s):  
Iolanda Ialongo ◽  
Jay Herman ◽  
Nick Krotkov ◽  
Lok Lamsal ◽  
Folkert Boersma ◽  
...  
Keyword(s):  
Air Quality ◽  
Relative Difference ◽  
Urban Site ◽  
High Latitudes ◽  
Ozone Monitoring Instrument ◽  
Weekly Cycle ◽  
Clear Sky ◽  
Standard Product ◽  
Weekly Cycles ◽  
Sky Conditions

Abstract. We present the comparison of satellite-based OMI (Ozone Monitoring Instrument) NO2 products with ground-based observations in Helsinki. OMI NO2 total columns, available from standard product (SP) and DOMINO algorithm, are compared with the measurements performed by the Pandora spectrometer in Helsinki in 2012. The relative difference between Pandora #21 and OMI SP retrievals is 4 % and −6 % for clear sky and all sky conditions, respectively. DOMINO NO2 retrievals showed slightly lower total columns with median differences about −5 % and −14 % for clear sky and all sky conditions, respectively. Large differences often correspond to cloudy autumn-winter days with solar zenith angles above 65°. Nevertheless, the differences remain within the retrieval uncertainties. Furthermore, the weekly and seasonal cycles from OMI, Pandora and NO2 surface concentrations are compared. Both satellite- and ground-based data show a similar weekly cycle, with lower NO2 levels during the weekend compared to the weekdays as result of reduced emissions from traffic and industrial activities. Also the seasonal cycle shows a similar behaviour, even though the results are affected by the fact that most of the data are available during spring-summer because of cloud cover in other seasons. This is one of few works in which OMI NO2 retrievals are evaluated in a urban site at high latitudes (60° N). Despite the city of Helsinki having relatively small pollution sources, OMI retrievals have proved to be able to describe air quality features and variability similar to surface observations. This adds confidence in using satellite observations for air quality monitoring also at high latitudes.

Satellite measurements of the clear-sky greenhouse effect from tropospheric ozone

2008 ◽  
Vol 1 (5) ◽  
pp. 305-308 ◽  
Author(s):  
Helen M. Worden ◽  
Kevin W. Bowman ◽  
John R. Worden ◽  
Annmarie Eldering ◽  
Reinhard Beer
Keyword(s):  
Greenhouse Effect ◽  
Tropospheric Ozone ◽  
Satellite Measurements ◽  
Clear Sky

scholarly journals Quantifying the Drivers of the Clear Sky Greenhouse Effect, 2000–2016

2019 ◽  
Vol 124 (21) ◽  
pp. 11354-11371 ◽  
Author(s):  
Shiv Priyam Raghuraman ◽  
David Paynter ◽  
V. Ramaswamy
Keyword(s):  
Greenhouse Effect ◽  
Clear Sky

Distinctive Roles of Air–Sea Coupling on Different MJO Events: A New Perspective Revealed from the DYNAMO/CINDY Field Campaign*

2015 ◽  
Vol 143 (3) ◽  
pp. 794-812 ◽  
Author(s):  
Xiouhua Fu ◽  
Wanqiu Wang ◽  
June-Yi Lee ◽  
Bin Wang ◽  
Kazuyoshi Kikuchi ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Large Scale ◽  
Essential Role ◽  
Intraseasonal Variability ◽  
Physical Processes ◽  
Field Campaign ◽  
Strongly Coupled ◽  
The Indian Ocean ◽  
New Perspective ◽  
Sst Anomalies

Abstract Previous observational analysis and modeling studies indicate that air–sea coupling plays an essential role in improving MJO simulations and extending MJO forecasting skills. However, whether the SST feedback plays an indispensable role for the existence of the MJO remains controversial, and the precise physical processes through which the SST feedback may lead to better MJO simulations and forecasts remain elusive. The DYNAMO/Cooperative Indian Ocean Experiment on Intraseasonal Variability in the Year 2011 (CINDY) field campaign recently completed over the Indian Ocean reveals a new perspective and provides better data to improve understanding of the MJO. It is found that among the five MJO events that occurred during the DYNAMO/CINDY field campaign, only two MJO events (the November and March ones) have robust SST anomalies associated with them. For the other three MJO events (the October, December, and January ones), no coherent SST anomalies are observed. This observational scenario suggests that the roles of air–sea coupling on the MJO vary greatly from event to event. To elucidate the varying roles of air–sea coupling on different MJO events, a suite of hindcast experiments was conducted with a particular focus on the October and November MJO events. The numerical results confirm that the October MJO is largely controlled by atmospheric internal dynamics, while the November MJO is strongly coupled with underlying ocean. For the November MJO event, the positive SST anomalies significantly improve MJO forecasting by enhancing the response of a Kelvin–Rossby wave couplet, which prolongs the feedback between convection and large-scale circulations, and thus favors the development of stratiform rainfall, in turn, facilitating the production of eddy available potential energy and significantly amplifying the intensity of the model November MJO.

Solar Orbiter: Europe's mission to the Sun

2020 ◽  
Author(s):  
Yannis Zouganelis ◽  
Daniel Mueller ◽  
Chris St Cyr ◽  
Holly Gilbert ◽  
Teresa Nieves-Chinchilla
Keyword(s):  
High Spatial Resolution ◽  
Solar Wind Plasma ◽  
Ecliptic Plane ◽  
Current Status ◽  
Polar Regions ◽  
The Sun ◽  
Physical Processes ◽  
New Perspective ◽  
Orbiter Mission

&lt;p&gt;&lt;span&gt;ESA&amp;#8217;s Solar Orbiter mission is scheduled for launch in February 2020, and will focus on exploring the linkage between the Sun and the heliosphere. It is a collaborative mission with NASA that will collect unique data that will allow us to study, e.g., the coupling between macroscopic physical processes to those on kinetic scales, the generation of solar energetic particles and their propagation into the heliosphere, and the origin and acceleration of solar wind plasma. By approaching as close as 0.28 AU, Solar Orbiter will view the Sun with high spatial resolution and combine this with in-situ measurements of the surrounding heliosphere. Over the course of the mission, the highly elliptical orbit will get progressively more inclined to the ecliptic plane. Thanks to this new perspective, Solar Orbiter will deliver images and comprehensive data of the unexplored Sun&amp;#8217;s polar regions and the side of the Sun not visible from Earth. This talk will provide a mission overview, highlight synergies with NASA&amp;#8217;s Parker Solar Probe and summarise current status.&lt;/span&gt;&lt;/p&gt;

scholarly journals NEW PERSPECTIVE ON SPACE AND TIME FROM LORENTZ VIOLATION

2013 ◽  
Vol 28 (03) ◽  
pp. 1340012 ◽  
Author(s):  
BO-QIANG MA
Keyword(s):  
Lorentz Violation ◽  
Physical Processes ◽  
Space And Time ◽  
New Perspective

I present a brief review on space and time in different periods of physics, and then talk on the nature of space and time from physical arguments. I discuss the ways to test such a new perspective on space and time through searching for Lorentz violation in some physical processes. I also make an introduce to a newly proposed theory of Lorentz violation from basic considerations.

A new perspective on chemical and physical processes: the reaction force

2007 ◽  
Vol 105 (19-22) ◽  
pp. 2619-2625 ◽  
Author(s):  
A. Toro-Labbé ◽  
S. Gutiérrez-Oliva ◽  
J. S. Murray ◽  
P. Politzer
Keyword(s):  
Reaction Force ◽  
Physical Processes ◽  
New Perspective
Sign in / Sign up

Export Citation Format

Share Document