Long-term Trend Comparison of Planetary Boundary Layer Height in Observations and CMIP6 models over China

2021 ◽  
pp. 1-64
Author(s):  
Man Yue ◽  
Minghuai Wang ◽  
Jianping Guo ◽  
Haipeng Zhang ◽  
Xinyi Dong ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Planetary Boundary Layer ◽  
Climate Models ◽  
Radiative Effect ◽  
Term Trend ◽  
Cloud Radiative Effect ◽  
Long Term Trend ◽  
Long Term Variations

AbstractThe planetary boundary layer (PBL) plays an essential role in climate and air quality simulations. Nevertheless, large uncertainties remain in understanding the drivers for long-term trend of PBL height (PBLH) and its simulation. Here we combinate the radiosonde data and reanalysis datasets to analyze PBLH long-term trends over China, and to further explore the performance of CMIP6 climate models in simulating these trends. Results show that the observed long-term “positive to negative” trend shift of PBLH is related to the variation in the surface upward sensible heat flux (SHFLX), and the SHFLX is further controlled by the synergistic effect of low cloud cover (LCC) and soil moisture (SM) changes. Variabilities in LCC and SM directly influence the energy balance via surface net downward shortwave flux (SWF) and the latent heat flux (LHFLX), respectively. The CMIP6 climate models, however, cannot reproduce the observed PBLH long-term trend shift over China. The CMIP6 results illustrate an overwhelming continuous downward PBLH trend during the 1979–2014 period, which is largely caused by the poor capability in simulating long-term variations of cloud radiative effect. Our results reveal that the long-term cloud radiative effect simulation is critical for CMIP6 models in reproducing the long-term trend of PBLH. This study highlights the importance of processes associated with LCC and SM in modulating PBLH long-term variations and calls attentions to improve these processes in climate models in order to improve the PBLH long-term trend simulations.

Long-term Trend of Planetary Boundary Layer Height in Climate Models and Observations over East Asia

2020 ◽  
Author(s):  
Man Yue ◽  
Minghuai Wang
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
East Asia ◽  
Planetary Boundary Layer ◽  
Climate Models ◽  
Sensible Heat Flux ◽  
Sensible Heat ◽  
Term Trend ◽  
Long Term Trend

<p>Abstract: Planetary boundary layer (PBL) plays an important role in climate and air quality simulations. Large uncertainties remain in understanding the long-term trend of PBL height (PBLH). In this study, radiosonde data and ERA-Interim reanalysis data are applied to reveal the critical climate factors and mechanisms dominating the long-term trend of PBLH over East Asia. Our results show that, observed long-term shift in PBLH trend is found to be consistent with changes in sensible heat flux (SHFLX), net downward surface shortwave flux (SWFLX) and low cloud cover (LCC). Increases in soil moisture and LCC in recent years can modulate the energy partition through the SHFLX and modifying the surface radiation budget, and further lead to the long-term shift trend of PBLH. Long-term trend of PBLH over East Asia is further examined in climate models (including NCAR CESM2) and data from the Coupled Model Inter-comparison Project Phase 6 (CMIP6) experiments. The global climate models are not able to reproduce the long-term trend of PBLH over East Asia. CESM2 is shown to not catch the long-term variability of sensible heat flux and surface shortwave flux. Further analysis is performed to examine how the trend of mean PBLH and extreme low PBLH may be different.</p>

Long-term Trend Comparison of Planetary Boundary Layer Height in Observations and CMIP6 models over China

2021 ◽  
Author(s):  
Man Yue ◽  
Minghuai Wang ◽  
Jianping Guo ◽  
Haipeng Zhang ◽  
Xinyi Dong ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Cloud Cover ◽  
Climate Models ◽  
Term Trend ◽  
Cloud Radiative Effect ◽  
Low Cloud ◽  
Long Term Trends ◽  
Low Cloud Cover ◽  
Long Term Trend

<p>The planetary boundary layer (PBL) plays an essential role in climate and air quality simulations. Large uncertainties remain in understanding the long-term trend of PBL height (PBLH) and its simulation. Here we use the radiosonde data and reanalysis datasets to analyze PBLH long-term trends over China, and to further evaluate the performance of CMIP6 climate models in simulating these trends. Results show that the observed long-term “positive to negative” trend shift of PBLH is related to the variation in the surface upward sensible heat flux (SHFLX) which is further controlled by the synergistic effect of low cloud cover (LCC) and soil moisture (SM) changes. Variabilities in low cloud cover and soil moisture directly influence the energy balance via surface net downward shortwave flux (SWF) and the latent heat flux (LHFLX), respectively. We have found that the CMIP6 climate models cannot reproduce the observed PBLH long-term trend shift over China. The CMIP6 results show an overwhelming continuous downward PBLH trend during the 1979-2014 period, which is caused by the poorly simulated long-term changes of cloud radiative effect. Our results reveal that the long-term cloud radiative effect simulation is critical for CMIP6 models in reproducing the PBLH long-term trends. This study highlights the importance of low cloud cover and soil moisture processes in modulating PBLH long-term variations and calls attentions to improve these processes in climate models in order to improve the PLBH long-term trend simulations.</p>

Long-term variations of the oxygen red 630 nm line nightglow intensity

2007 ◽  
Vol 85 (2) ◽  
pp. 189-198 ◽  
Author(s):  
N B Gudadze ◽  
G G Didebulidze ◽  
G Sh. Javakhishvili ◽  
M G Shepherd ◽  
M V Vardosanidze
Keyword(s):  
Line Intensity ◽  
Peak Height ◽  
Mean Value ◽  
Lower Atmosphere ◽  
Data Set ◽  
Term Trend ◽  
Long Term Trend ◽  
Long Term Variations ◽  
Red Line

The long-term data set of total nightglow intensity of the oxygen red 630.0~nm line observed at Abastumani (41.8°N, 42.8°E) between 1957–1993 is investigated. The long-term trend and characteristic variations in solar radiation during an 11 year cycle of the red-line intensity are different after astronomical twilight (premidnight) and at midnight. The amplitude of deviation of the red-line intensity from its mean value at solar maximum and (or) minimum phase is greatest after astronomical twilight and decreases toward midnight. The long-term trend of these variations changes from its value about 0.74 R/year premidnight to its minimum negative value of about –1.92 R/year at and after midnight. This behavior of the long-term trend is considered as a possible result of an increase in electron density below the peak height (hmF2) of the ionospheric F2 layer and lowering of the height hmF2 after midnight predicted by the TIME-GCM model on the assumption of an increase in density of greenhouse gases in the lower atmosphere. The third-order regression equation (with different solar activity indices) is considered to be convenient for describing long-term variations in the mean annual red-line intensity.PACS Nos.: 94.10.Rk, 94.20.Ji, 92.60.Vb

scholarly journals Persistent Atmospheric and Oceanic Anomalies in the North Atlantic from Summer 2009 to Summer 2010

2011 ◽  
Vol 24 (22) ◽  
pp. 5812-5830 ◽  
Author(s):  
Zeng-Zhen Hu ◽  
Arun Kumar ◽  
Bohua Huang ◽  
Yan Xue ◽  
Wanqiu Wang ◽  
...  
Keyword(s):  
Heat Flux ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
Negative Phase ◽  
Atlantic Basin ◽  
Term Trend ◽  
The North ◽  
The North Atlantic ◽  
Long Term Trend

Abstract In this work, the authors analyze the air–sea interaction processes associated with the persistent atmospheric and oceanic anomalies in the North Atlantic Ocean during summer 2009–summer 2010 with a record-breaking positive sea surface temperature anomaly (SSTA) in the hurricane Main Development Region (MDR) in the spring and summer of 2010. Contributions to the anomalies from the El Niño–Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), and a long-term trend are identified. The warming in the tropical North Atlantic during summer 2009–summer 2010 represented a typical response to ENSO, preconditioned and amplified by the influence of a strong and persistent negative phase of the NAO. The long-term trends enhanced the warming in the high and low latitudes and weakened the cooling in the midlatitudes. The persistent negative phase of the NAO was associated with active thermodynamic air–sea interaction in the North Atlantic basin. Surface wind anomalies associated with the NAO altered the ocean surface heat flux and changed the SSTA, which was likely further enhanced by the positive wind speed–evaporation–SST feedback. The total heat flux was dominated by the latent and sensible heat fluxes, while the shortwave radiation contributed to the tropical SSTA to a lesser degree. Sensitivity experiments with an atmospheric general circulation model forced by observed SST in the Atlantic Ocean alone suggested that the Atlantic SSTA, which was partly forced by the NAO, had some positive contribution to the persistence of the negative phase of the NAO. Therefore, the persistent NAO condition is partly an outcome of the global climate anomalies and the ocean–atmosphere feedback within the Atlantic basin. The combination of the ENSO, NAO, and long-term trend resulted in the record-breaking positive SSTA in the MDR in the boreal spring and summer of 2010. On the basis of the statistical relationship, the SSTA pattern in the North Atlantic was reasonably well predicted by using the preceding ENSO and NAO as predictors.

scholarly journals Historical (1850–2000) gridded anthropogenic and biomass burning emissions of reactive gases and aerosols: methodology and application

2010 ◽  
Vol 10 (2) ◽  
pp. 4963-5019 ◽  
Author(s):  
J.-F. Lamarque ◽  
T. C. Bond ◽  
V. Eyring ◽  
C. Granier ◽  
A. Heil ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Climate Models ◽  
Climate Model ◽  
Historical Period ◽  
Term Trend ◽  
Model Simulations ◽  
Reactive Gases ◽  
Long Term Trend ◽  
Good Agreement

Abstract. We present and discuss a new dataset of gridded emissions covering the historical period (1850–2000) in decadal increments at a horizontal resolution of 0.5° in latitude and longitude. The primary purpose of this inventory is to provide consistent gridded emissions of reactive gases and aerosols for use in chemistry model simulations needed by climate models for the Climate Model Intercomparison Program #5 (CMIP5) in support of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). Our best estimate for the year 2000 inventory represents a combination of existing regional and global inventories to capture the best information available at this point; 40 regions and 12 sectors are used to combine the various sources. The historical reconstruction of each emitted compound, for each region and sector, is then forced to agree with our 2000 estimate, ensuring continuity between past and 2000 emissions. Simulations from two chemistry-climate models is used to test the ability of the emission dataset described here to capture long-term changes in atmospheric ozone, carbon monoxide and aerosol distributions. The simulated long-term change in the Northern mid-latitudes surface and mid-troposphere ozone is not quite as rapid as observed. However, stations outside this latitude band show much better agreement in both present-day and long-term trend. The model simulations indicate that the concentration of carbon monoxide is underestimated at the Mace Head station; however, the long-term trend over the limited observational period seems to be reasonably well captured. The simulated sulfate and black carbon deposition over Greenland is in very good agreement with the ice-core observations spanning the simulation period. Finally, aerosol optical depth and additional aerosol diagnostics are shown to be in good agreement with previously published estimates and observations.

scholarly journals A long-term study of aerosol–cloud interactions and their radiative effect at a mid latitude continental site using ground-based measurements

2016 ◽  
Author(s):  
Elisa T. Sena ◽  
Allison McComiskey ◽  
Graham Feingold
Keyword(s):  
Great Plains ◽  
Climate Models ◽  
Cloud Droplet ◽  
Droplet Size Distribution ◽  
Radiative Effect ◽  
Aerosol Cloud ◽  
Long Term Study ◽  
Cloud Radiative Effect ◽  
Aerosol Cloud Interactions

Abstract. Empirical estimates of the microphysical response of cloud droplet size distribution to aerosol perturbations are commonly used to constrain aerosol–cloud interactions in climate models. Instead of empirical microphysical estimates, here macroscopic variables are analyzed to address the influences of aerosol particles and meteorological descriptors on instantaneous cloud albedo and radiative effect of shallow liquid water clouds. Long-term ground-based measurements from the Atmospheric Radiation Measurement (ARM) Program over the Southern Great Plains are used. A broad statistical analysis was performed on 14-years of coincident measurements of low clouds, aerosol and meteorological properties. Two cases representing conflicting results regarding the relationship between the aerosol and the cloud radiative effect were selected and studied in greater detail. Microphysical estimates are shown to be very uncertain and to depend strongly on the methodology, retrieval technique, and averaging scale. For this continental site, the results indicate that the influence of aerosol on shallow cloud radiative effect and albedo is weak and that macroscopic cloud properties and dynamics play a much larger role in determining the instantaneous cloud radiative effect compared to microphysical effects.

A Climatology of Clouds in Marine Cold Air Outbreaks in Both Hemispheres

2016 ◽  
Vol 29 (18) ◽  
pp. 6677-6692 ◽  
Author(s):  
Jennifer K. Fletcher ◽  
Shannon Mason ◽  
Christian Jakob
Keyword(s):  
Climate Models ◽  
Cloud Fraction ◽  
Satellite Observations ◽  
Radiative Effect ◽  
Cold Air ◽  
Cloud Properties ◽  
Cold Air Outbreak ◽  
Cloud Radiative Effect ◽  
Cold Air Outbreaks

Abstract A climatology of clouds within marine cold air outbreaks, primarily using long-term satellite observations, is presented. Cloud properties between cold air outbreaks in different regions in both hemispheres are compared. In all regions marine cold air outbreak clouds tend to be low level with high cloud fraction and low-to-moderate optical thickness. Stronger cold air outbreaks have clouds that are optically thicker, but not geometrically thicker, than those in weaker cold air outbreaks. There is some evidence that clouds deepen and break up over the course of a cold air outbreak event. The top-of-the-atmosphere longwave cloud radiative effect in cold air outbreaks is small because the clouds have low tops. However, their surface longwave cloud radiative effect is considerably larger. The rarity of cold air outbreaks in summer limits their shortwave cloud radiative effect. They do not contribute substantially to global shortwave cloud radiative effect and are, therefore, unlikely to be a major source of shortwave cloud radiative effect errors in climate models.

scholarly journals Historical (1850–2000) gridded anthropogenic and biomass burning emissions of reactive gases and aerosols: methodology and application

2010 ◽  
Vol 10 (15) ◽  
pp. 7017-7039 ◽  
Author(s):  
J.-F. Lamarque ◽  
T. C. Bond ◽  
V. Eyring ◽  
C. Granier ◽  
A. Heil ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Climate Models ◽  
Climate Model ◽  
Historical Period ◽  
Term Trend ◽  
Model Simulations ◽  
Reactive Gases ◽  
Long Term Trend ◽  
Good Agreement

Abstract. We present and discuss a new dataset of gridded emissions covering the historical period (1850–2000) in decadal increments at a horizontal resolution of 0.5° in latitude and longitude. The primary purpose of this inventory is to provide consistent gridded emissions of reactive gases and aerosols for use in chemistry model simulations needed by climate models for the Climate Model Intercomparison Program #5 (CMIP5) in support of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment report (AR5). Our best estimate for the year 2000 inventory represents a combination of existing regional and global inventories to capture the best information available at this point; 40 regions and 12 sectors are used to combine the various sources. The historical reconstruction of each emitted compound, for each region and sector, is then forced to agree with our 2000 estimate, ensuring continuity between past and 2000 emissions. Simulations from two chemistry-climate models are used to test the ability of the emission dataset described here to capture long-term changes in atmospheric ozone, carbon monoxide and aerosol distributions. The simulated long-term change in the Northern mid-latitudes surface and mid-troposphere ozone is not quite as rapid as observed. However, stations outside this latitude band show much better agreement in both present-day and long-term trend. The model simulations indicate that the concentration of carbon monoxide is underestimated at the Mace Head station; however, the long-term trend over the limited observational period seems to be reasonably well captured. The simulated sulfate and black carbon deposition over Greenland is in very good agreement with the ice-core observations spanning the simulation period. Finally, aerosol optical depth and additional aerosol diagnostics are shown to be in good agreement with previously published estimates and observations.

NAEP Trends: Main NAEP vs. Long-Term Trend

2010 ◽  
Author(s):  
Albert E. Beaton ◽  
James R. Chromy
Keyword(s):  
Term Trend ◽  
Long Term Trend
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