The Energetics and Magnitude of Hydrometeor Friction in Clouds

Igel, Matthew R.; Igel, Adele L.

doi:10.1175/jas-d-17-0285.1

Cited by 4 publications

(1 citation statement)

References 25 publications

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“…Note the following differences in notations between Sabuwala et al (2015) and the present work: T s → T b , Qin → J, Qd → D, P → W P = gH P P (for the last relation see Pauluis et al, 2000;Makarieva et al, 2013). (The "diabatic case" of Sabuwala et al (2015) addressed thermal dissipation of the potential energy of the falling droplets (see Igel and Igel, 2018). )…”

Section: The Estimate Of Sabuwala Et Al (2015)mentioning

confidence: 95%

Water lifting and outflow gain of kinetic energy in tropical cyclones

Makarieva¹,

Gorshkov²,

Nefiodov³

et al. 2021

Preprint

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While water lifting plays a recognized role in the global atmospheric power budget, estimates for this role in tropical cyclones vary from zero to a major reduction in storm intensity. To assess its impact, here we consider work output of an infinitely narrow thermodynamic cycle with two adiabats connecting the top of the boundary layer in the vicinity of maximum wind to an arbitrary level in the inviscid free troposphere. The reduction of storm's maximum wind speed due to water lifting is found to decline with increasing efficiency of the cycle and is about 3% for maximum observed Carnot efficiencies. In the steady-state cycle, there is an extra heat input associated with the warming of precipitating water. The corresponding positive extra work is of an opposite sign, and several times smaller than, the water lifting. We also estimate the gain of kinetic energy in the outflow region. Contrary to previous assessments, this term in the storm power budget is found to be large when the outflow radius is small (comparable to the radius of maximum wind). Using the established framework, we show that Emanuel's maximum potential intensity corresponds to a cycle where total work equals work performed at the top of the boundary layer (net work in the free troposphere is zero). This constrains a dependence between the outflow temperature and heat input at the point of maximum wind, but does not constrain the radial pressure gradient. Implications of the established patterns for assessing real storms are outlined.

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Section: The Estimate Of Sabuwala Et Al (2015)mentioning

confidence: 95%

Water lifting and outflow gain of kinetic energy in tropical cyclones

Makarieva¹,

Gorshkov²,

Nefiodov³

et al. 2021

Preprint

View full text Add to dashboard Cite

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The Nontraditional Coriolis Terms and Tropical Convective Clouds

Igel

Biello

2020

Journal of the Atmospheric Sciences

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The full, three-dimensional Coriolis force includes the familiar sine-of-latitude terms as well as frequently dropped cosine-of-latitude terms (Nontraditional Coriolis Terms [NCT]). The latter are often ignored because they couple the zonal and vertical momentum equations which in the large-scale limit of weak vertical velocity is considered insignificant almost everywhere. Here, we ask whether equatorial mesoscale clouds which fall outside the large-scale limit are affected by the NCT. A simple scaling indicates that a Lagrangian parcel convecting at 10 ms−1 through the depth of the troposphere should be deflected over 2 km to the west. To understand the real impact of NCT, we develop a mathematical framework which describes an azimuthally symmetric convective circulation with an analytical expression for an incompressible poloidal flow. Because the model incorporates the full 3-dimensional flow associated with convection, it uniquely predicts not only the westward tilt of clouds but also a meridional diffluence of western cloud outflow. To test these predictions, we perform a set of cloud-resolving simulations whose results show preferential lifting of surface parcels with positive zonal momentum and zonal asymmetry in convective strength. RCE simulations show changes to the organization of coherent precipitation regions and a decrease in mean convective intensity of approximately 2 ms−1 above the freezing level. An additional pair of dry cloud-resolving simulations designed to mimic the steady state flow of the model show maximum perturbations to the upper level zonal flow of 8 ms−1. Together, the numerical and analytic results suggest the NCT consequentially alter equatorial mesoscale convective circulations and should be considered in conceptual models.

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Water Lifting and Outflow Gain of Kinetic Energy in Tropical Cyclones

Makarieva

Gorshkov

Nefiodov

et al. 2023

Journal of the Atmospheric Sciences

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While water lifting plays a recognized role in the global atmospheric power budget, estimates for this role in tropical cyclones vary from no effect to a major reduction in storm intensity. To better assess this impact, here we consider the work output of an infinitely narrow thermodynamic cycle with two streamlines connecting the top of the boundary layer in the vicinity of maximum wind (without assuming gradient-wind balance) to an arbitrary level in the inviscid free troposphere. The reduction of a storm’s maximum wind speed due to water lifting is found to decline with increasing efficiency of the cycle and is about 5% for maximum observed Carnot efficiencies. In the steady-state cycle, there is an extra heat input associated with the warming of precipitating water. The corresponding positive extra work is of an opposite sign and several times smaller than that due to water lifting. We also estimate the gain of kinetic energy in the outflow region. Contrary to previous assessments, this term is found to be large when the outflow radius is small (comparable to the radius of maximum wind). Using our framework, we show that Emanuel’s maximum potential intensity (E-PI) corresponds to a cycle where total work equals work performed at the top of the boundary layer (net work in the free troposphere is zero). This constrains a dependence between the outflow temperature and heat input at the point of maximum wind, but does not constrain the radial pressure gradient. We outline the implications of the established patterns for assessing real storms.

show abstract

The Energetics and Magnitude of Hydrometeor Friction in Clouds

Cited by 4 publications

References 25 publications

Water lifting and outflow gain of kinetic energy in tropical cyclones

Water lifting and outflow gain of kinetic energy in tropical cyclones

The Nontraditional Coriolis Terms and Tropical Convective Clouds

Water Lifting and Outflow Gain of Kinetic Energy in Tropical Cyclones

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