An assessment of the radiative effects of ice supersaturation based on in situ observations

Tan, Xiao; Huang, Yi; Diao, Minghui; Bansemer, Aaron; Zondlo, M. A.; DiGangi, J. P.; Volkamer, Rainer; Hu, Yongyun

doi:10.1002/2016gl071144

Cited by 11 publications

(11 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Tan et al (2016) showed that misrepresenting ISS conditions as cirrus clouds can lead to significant radiative forcing biases in a vertical column with an average of ~4.2 W m −2 increase in the net radiation at the top of the atmosphere. In addition, Diao et al (2014) compared the distributions of clear-sky ISS conditions between the Northern and Southern Hemispheres and pointed out that more sampling in the Southern Hemisphere is needed to examine the relationship between the ISS occurrence frequency and aerosol concentration.…”

Section: Cloud Microphysicsmentioning

confidence: 99%

The O2/N2 Ratio and CO2 Airborne Southern Ocean Study

Stephens

Long

Keeling

et al. 2018

Bulletin of the American Meteorological Society

Self Cite

View full text Add to dashboard Cite

A s the primary conduit for CO 2 and heat exchange between the atmosphere and the deep ocean, the Southern Ocean is an important part of the climate system. Approximately 40% of the ocean's inventory of anthropogenic carbon entered through the air-sea interface south of 40°S (Khatiwala et al. 2009), and the region will continue to serve as an important carbon sink into the future (Ito et al. 2015). Despite its importance, the processes controlling air-sea gas exchange in the Southern Ocean are poorly represented by models. This was highlighted in a recent comparison of models from phase 5 of the Coupled Model Intercomparison Project (CMIP5), wherein the simulated seasonal cycles of air-sea CO 2 exchange with the Southern Ocean were widely divergent and in poor agreement with observational estimates (Anav et al. 2013;Jiang et al. 2014), suggesting possible model biases in the timing, spatial A recent Southern Ocean airborne campaign collected continuous, discrete, and remote sensing measurements to investigate biogeochemical and physical processes driving air-sea exchange of CO 2 , O 2 , and reactive biogenic gases.

show abstract

Section: Cloud Microphysicsmentioning

confidence: 99%

The O2/N2 Ratio and CO2 Airborne Southern Ocean Study

Stephens

Long

Keeling

et al. 2018

Bulletin of the American Meteorological Society

Self Cite

View full text Add to dashboard Cite

show abstract

“…Zhang et al, 2014). The PDFs of sub-grid-scale distributions can be sampled on sub-columns for cloud microphysics (Thayer-Calder et al, 2015). With the increase of model resolutions for future global model developments, the sub-grid variability of temperature, moisture, and cloud microphysics and dynamics will be better resolved.…”

Section: Discussionmentioning

confidence: 99%

Respones to Referee #1 comments

Liu¹

2017

Preprint

View full text Add to dashboard Cite

In this study we evaluate cloud properties simulated by the Community Atmosphere Model version 5 (CAM5) using in situ measurements from the HIAPER Poleto-Pole Observations (HIPPO) campaign for the period of 2009 to 2011. The modeled wind and temperature are nudged towards reanalysis. Model results collocated with HIPPO flight tracks are directly compared with the observations, and model sensitivities to the representations of ice nucleation and growth are also examined. Generally, CAM5 is able to capture specific cloud systems in terms of vertical configuration and horizontal extension. In total, the model reproduces 79.8 % of observed cloud occurrences inside model grid boxes and even higher (94.3 %) for ice clouds (T ≤ −40 • C). The missing cloud occurrences in the model are primarily ascribed to the fact that the model cannot account for the high spatial variability of observed relative humidity (RH). Furthermore, model RH biases are mostly attributed to the discrepancies in water vapor, rather than temperature. At the micro-scale of ice clouds, the model captures the observed increase of ice crystal mean sizes with temperature, albeit with smaller sizes than the observations. The model underestimates the observed ice number concentration (N i ) and ice water content (IWC) for ice crystals larger than 75 µm in diameter. Modeled IWC and N i are more sensitive to the threshold diameter for autoconversion of cloud ice to snow (D cs ), while simulated ice crystal mean size is more sensitive to ice nucleation parameterizations than to D cs . Our results highlight the need for further improvements to the sub-grid RH variability and ice nucleation and growth in the model.

show abstract

“…Measurements are separated by cloud condition whereas in-cloud condition is defined by the presence of at least one ice crystal from the Fast 2-DC probe (Ni > 0 L -1 ). The same in-cloud definition has been used by several previous studies (D'Alessandro et al, 2017;Diao et al, 2014aDiao et al, , 2014bDiao et al, , 2015Diao et al, , 2017Tan et al, 2016), and all other samples are defined as clear sky. For regional variation analysis, data are binned by six latitudinal regions in the two hemispheres, that is, NH polar (60ºN -90ºN), SH polar (60ºS -90ºS), NH midlatitude (30ºN -60ºN), SH midlatitude (30ºS -60ºS), NH tropics (0º -30ºN), and SH tropics (0º -30ºS).…”

Section: In Situ Observations and Instrumentationsmentioning

confidence: 99%

“…Unlike most other cloud types, cirrus clouds may produce a net positive or negative radiative forcing depending on their microphysical properties (Stephens and Webster, 1981; Zhang et al, 1999), which are affected by meteorological conditions and aerosol distributions. Tan et al (2016) showed that the radiative effects…”

mentioning

confidence: 99%

Effects of Thermodynamics, Dynamics and Aerosols on Cirrus Clouds Based on In Situ Observations and NCAR CAM6 Model

Patnaude¹,

Diao²,

Liu³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Cirrus cloud radiative effects are largely affected by ice microphysical properties, including ice water content (IWC), ice crystal number concentration (Ni) and mean diameter (Di). These characteristics vary significantly due to thermodynamic, dynamical and aerosol conditions. In this work, a global-scale observation dataset is used to examine regional variations of cirrus cloud microphysical properties, as well as several key controlling factors, i.e., temperature, relative humidity with respect to ice (RHi), vertical velocity (w), and aerosol number concentrations (Na). Results are compared with simulations from the National Center for Atmospheric Research (NCAR) Community Atmosphere Model version 6 (CAM6). The differences between simulations and observations are found to vary with latitude and temperature. Specifically, simulations are found to underestimate IWC by a factor of 5–30 in all regions. Simulated Ni is overestimated in most regions except Northern Hemisphere midlatitude and polar regions. Simulated Di is underestimated, especially for warmer conditions (−50 °C to −40 °C) and higher Na, possibly due to less effective ice particle growth/sedimentation and weaker aerosol indirect effects, respectively. For RHi effects, the frequency and magnitude of ice supersaturation is underestimated in simulations for clear-sky conditions, and the simulated IWC and Ni show maximum values at 80 % RHi instead of 110 % as observed. For w effects, both observations and simulations show variances of w (σw) decreasing from tropics to polar regions, but simulations show much higher σw for in-cloud condition than clear-sky condition. These findings provide an observation-based guideline for improving simulated ice microphysical properties and their relationships with key controlling factors at various geographical locations.

show abstract

An assessment of the radiative effects of ice supersaturation based on in situ observations

Cited by 11 publications

References 48 publications

The O2/N2 Ratio and CO2 Airborne Southern Ocean Study

The O2/N2 Ratio and CO2 Airborne Southern Ocean Study

Respones to Referee #1 comments

Effects of Thermodynamics, Dynamics and Aerosols on Cirrus Clouds Based on In Situ Observations and NCAR CAM6 Model

Contact Info

Product

Resources

About