The Role of Low-Level Convergence and Latent Heating in a Simulation of Observed Squall Line Formation

Abstract Analysis of a strong landfalling atmospheric river is presented that compares the evolution of a control simulation with that of an adjoint-derived perturbed simulation using the Coupled Ocean–Atmosphere Mesoscale Prediction System. The initial-condition sensitivities are optimized for all state variables to maximize the accumulated precipitation within the majority of California. The water vapor transport is found to be substantially enhanced at the California coast in the perturbed simulation during the time of peak precipitation, demonstrating a strengthened role of the orographic precipitation forcing. Similarly, moisture convergence and vertical velocities derived from the transverse circulation are found to be substantially enhanced during the time of peak precipitation, also demonstrating a strengthened role of the dynamic component of the precipitation. Importantly, both components of precipitation are associated with enhanced latent heating by which (i) a stronger diabatically driven low-level potential vorticity anomaly strengthens the low-level wind (and thereby the orographic precipitation forcing), and (ii) greater moist diabatic forcing enhances the Sawyer–Eliassen transverse circulation and thereby increases ascent and dynamic precipitation. A Lagrangian parcel trajectory analysis demonstrates that a positive moisture perturbation within the atmospheric river increases the moisture transport into the warm conveyor belt offshore, which enhances latent heating in the perturbed simulation. These results suggest that the precipitation forecast in this case is particularly sensitive to the initial moisture content within the atmospheric river due to its role in enhancing both the orographic precipitation forcing and the dynamic component of precipitation.

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How Does Latent Cooling Affect Baroclinic Development in an Idealized Framework?

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-18-0372.1 ◽

2019 ◽

Vol 76 (9) ◽

pp. 2701-2714 ◽

Cited By ~ 1

Author(s):

Kristine F. Haualand ◽

Thomas Spengler

Keyword(s):

Potential Energy ◽

Potential Vorticity ◽

Diabatic Heating ◽

Vertical Motion ◽

Latent Heating ◽

Low Level ◽

Available Potential Energy ◽

Relative Contribution ◽

Heating And Cooling

Abstract Latent cooling by evaporating or melting hydrometeors has recently been shown to contribute to the positive low-level potential vorticity (PV) anomaly below the layer of latent heating in midlatitude cyclones. While the low-level PV anomaly might be intensified by latent cooling, the influence on the overall baroclinic development remains unclear. Including both latent heating and cooling in the Eady model, this study finds that latent cooling reduces baroclinic growth. While the PV anomaly between the layers of latent cooling and heating increases for realistic heating intensities, the PV anomaly at the top of the heating layer decreases, as latent heating is weakened because of reduced vertical motion within the cyclone. Consequently, the relative contribution from diabatic heating to the generation of eddy available potential energy decreases when latent cooling is included. Thus, despite the recently emphasized role of evaporation for the low-level PV anomaly in developing cyclones, the overall effect of latent cooling is detrimental to baroclinic growth.

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Tryptophan-Niacin Metabolism in Rat with Puromycin Aminonucleoside-Induced Nephrosis

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831.76.1.28 ◽

2006 ◽

Vol 76 (1) ◽

pp. 28-33 ◽

Cited By ~ 7

Author(s):

Yukari Egashira ◽

Shin Nagaki ◽

Hiroo Sanada

Keyword(s):

Body Weight ◽

Urinary Excretion ◽

Enzyme Activities ◽

Treated Group ◽

Control Group ◽

Puromycin Aminonucleoside ◽

Low Level ◽

Key Enzyme

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidneyα-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.

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ROLE OF LIPID PROFILE IN OVARIAN CARCINOMA PATIENTS

International Journal of Medical and Biomedical Studies ◽

10.32553/ijmbs.v3i8.501 ◽

2019 ◽

Vol 3 (8) ◽

Author(s):

Dr. Manisha ◽

Dr. Ruchi Jindal

Keyword(s):

Ovarian Cancer ◽

Lipid Profile ◽

Cancer Patients ◽

Ovarian Tumor ◽

Ovarian Cancer Risk ◽

Low Level ◽

Medical College ◽

Group I ◽

History Of

Background: The term "ovarian cancer" includes several different types of cancer that arise from cells of the ovary, most commonly, tumors arise from the epithelium or lining cells of the ovary. Ovarian cancer risk is positively associated with higher consumption of dietary cholesterol and eggs, and inversely associated with a higher intake of vegetables. High consumption of fats may increase circulating estrogen levels, thus increasing the possibility of cell damage and proliferation that is responsible for cancerous growth. Material & Methods: The present study was conducted at Geetanjali Medical College and Hospital, Udaipur (Rajasthan). Total 100 cases (females) attending the obstetrics and gynecology department for some gynecological and other problem were selected for this study between the age of 40-60 years, who were attending cancer centre at GEETANJALI MEDICAL COLLEGE AND HOSPITAL, Udaipur (Rajasthan). GROUP I: - It consisted of healthy females control subjects (n=50) .By routine examination and tests, we ensured that all the subjects were healthy and there were no signs and symptoms or history of ovarian tumor and diseases GROUP II: - It consisted of ovarian cancer females subjects (n=50) with a history of ovarian tumor. Results: Higher level of cholesterol, LDL, VLDL and low level of HDL are found in ovarian cancer patients. Conclusion: The present study we highlights the importance and role of serum lipid profile in diagnosis, prognosis and recurrence of the disease. The study shows that serum level of cholesterol, LDL, VLDL was elevated in patients of ovarian cancer while low level of HDL are found in ovarian cancer patients. Key words: lipid profile, ovarian cancer.

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Role of the eastern Pacific-Caribbean Sea SST gradient in the Choco low-level jet variations from 1900–2015

Climate Research ◽

10.3354/cr01633 ◽

2021 ◽

Author(s):

WL Cerón ◽

RV Andreoli ◽

MT Kayano ◽

A Avila-Diaz

Keyword(s):

Caribbean Sea ◽

Eastern Pacific ◽

Low Level ◽

Low Level Jet ◽

Sst Gradient

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The Role of Equatorial Rossby Waves in Tropical Cyclogenesis. Part I: Idealized Numerical Simulations in an Initially Quiescent Background Environment

Monthly Weather Review ◽

10.1175/2009mwr3114.1 ◽

2010 ◽

Vol 138 (4) ◽

pp. 1368-1382 ◽

Cited By ~ 15

Author(s):

Jeffrey S. Gall ◽

William M. Frank ◽

Matthew C. Wheeler

Keyword(s):

Tropical Cyclone ◽

Large Scale ◽

Phase Speed ◽

Tropical Cyclogenesis ◽

Initial Amplitude ◽

Low Level ◽

Wave Simulation ◽

Horizontal Momentum ◽

Good Agreement

Abstract This two-part series of papers examines the role of equatorial Rossby (ER) waves in tropical cyclone (TC) genesis. To do this, a unique initialization procedure is utilized to insert n = 1 ER waves into a numerical model that is able to faithfully produce TCs. In this first paper, experiments are carried out under the idealized condition of an initially quiescent background environment. Experiments are performed with varying initial wave amplitudes and with and without diabatic effects. This is done to both investigate how the properties of the simulated ER waves compare to the properties of observed ER waves and explore the role of the initial perturbation strength of the ER wave on genesis. In the dry, frictionless ER wave simulation the phase speed is slightly slower than the phase speed predicted from linear theory. Large-scale ascent develops in the region of low-level poleward flow, which is in good agreement with the theoretical structure of an n = 1 ER wave. The structures and phase speeds of the simulated full-physics ER waves are in good agreement with recent observational studies of ER waves that utilize wavenumber–frequency filtering techniques. Convection occurs primarily in the eastern half of the cyclonic gyre, as do the most favorable conditions for TC genesis. This region features sufficient midlevel moisture, anomalously strong low-level cyclonic vorticity, enhanced convection, and minimal vertical shear. Tropical cyclogenesis occurs only in the largest initial-amplitude ER wave simulation. The formation of the initial tropical disturbance that ultimately develops into a tropical cyclone is shown to be sensitive to the nonlinear horizontal momentum advection terms. When the largest initial-amplitude simulation is rerun with the nonlinear horizontal momentum advection terms turned off, tropical cyclogenesis does not occur, but the convectively coupled ER wave retains the properties of the ER wave observed in the smaller initial-amplitude simulations. It is shown that this isolated wave-only genesis process only occurs for strong ER waves in which the nonlinear advection is large. Part II will look at the more realistic case of ER wave–related genesis in which a sufficiently intense ER wave interacts with favorable large-scale flow features.

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