A new approach for estimating entrainment rate in cumulus clouds

نویسندگان

  • Chunsong Lu
  • Yangang Liu
  • Seong Soo Yum
  • Shengjie Niu
  • Satoshi Endo
چکیده

[1] A new approach is presented to estimate entrainment rate in cumulus clouds. The new approach is directly derived from the definition of fractional entrainment rate and relates it to mixing fraction and the height above cloud base. The results derived from the new approach compare favorably with those obtained with a commonly used approach, and have smaller uncertainty. This new approach has several advantages: it eliminates the need for in-cloud measurements of temperature and water vapor content, which are often problematic in current aircraft observations; it has the potential for straightforwardly connecting the estimation of entrainment rate and the microphysical effects of entrainmentmixing processes; it also has the potential for developing a remote sensing technique to infer entrainment rate. Citation: Lu, C., Y. Liu, S. S. Yum, S. Niu, and S. Endo (2012), A new approach for estimating entrainment rate in cumulus clouds, Geophys. Res. Lett., 39, L04802, doi:10.1029/2011GL050546.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Empirical relationship between entrainment rate and microphysics in cumulus clouds

[1] The relationships between fractional entrainment rate and key microphysical quantities (e.g., liquid water content, droplet number concentration, volume mean radius, and standard deviation of cloud droplet size distributions) in shallow cumuli are empirically examined using in situ aircraft observations from the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optic...

متن کامل

Variation in entrainment rate and relationship with cloud microphysical properties on the scale of 5 m

This paper focuses on the variability in entrainment rate in individual cumulus clouds using the entrainment rate estimated on the scale of 5 m in 186 shallow cumulus clouds from eight aircraft flights, using in situ observations from the RACORO field campaign (the routine atmospheric radiation measurement aerial facility clouds with low optical water depths optical radiative observations) over...

متن کامل

Factors Limiting Convective Cloud-Top Height at the ARM Nauru Island Climate Research Facility

Cumulus congestus clouds, with moderate shortwave albedos and cloud-top temperatures near freezing, occur fairly often in the Tropics. These clouds may play an important role in the evolution of the Madden– Julian oscillation and the regulation of relative humidity in the midtroposphere. Despite this importance they are not necessarily simulated very well in global climate models. Surface remot...

متن کامل

Scale dependence of entrainment-mixing mechanisms in cumulus clouds

This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all ty...

متن کامل

Estimating the Evaporative Cooling Bias of an Airborne Reverse Flow Thermometer

Airborne reverse flow immersion thermometers were designed to prevent sensor wetting in cloud. Yet there is strong evidence that some wetting does occur and therefore also sensor evaporative cooling as the aircraft exits a cloud. Numerous penetrations of cumulus clouds in a broad range of environmental and cloud conditions are used to estimate the resulting negative temperature bias. This cloud...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2012