scholarly journals Tests of Monte Carlo Independent Column Approximation in the ECHAM5 Atmospheric GCM

2007 ◽  
Vol 20 (19) ◽  
pp. 4995-5011 ◽  
Author(s):  
P. Räisänen ◽  
S. Järvenoja ◽  
H. Järvinen ◽  
M. Giorgetta ◽  
E. Roeckner ◽  
...  

Abstract The Monte Carlo Independent Column Approximation (McICA) method for computing domain-average radiative fluxes allows a flexible treatment of unresolved cloud structure, and it is unbiased with respect to the full ICA, but its flux estimates contain conditional random noise. Here, tests of McICA in the ECHAM5 atmospheric GCM are reported. ECHAM5 provides an interesting test bed for McICA because it carries prognostic variables for the subgrid-scale probability distribution of total water content, which allows us to determine subgrid-scale cloud variability directly from the resolved-scale model variables. Three experiments with differing levels of radiative noise, each consisting of ten 6-yr runs, are performed to estimate the impact of McICA noise on simulated climate. In an experiment that attempted to deliberately maximize McICA noise, a systematic reduction in low cloud fraction occurred. For a more reasonable implementation of McICA, the impact of noise is very small, although statistically discernible. In terms of the impacts of noise, McICA appears to be a viable approach for use in ECHAM5. However, to improve the simulation of cloud radiative effects, realistic representation of both unresolved and resolved cloud structures is needed, which remains a challenging problem. Comparison of ECHAM5 data with a global cloud system–resolving model dataset and with International Satellite Cloud Climatology Project data suggested two problems related to unresolved cloud structures. First, ECHAM5 appears to underestimate subgrid-scale cloud variability. This problem seems partly related to the use of the beta distribution scheme for total water content in ECHAM5: in its current form, the scheme is unable to generate highly inhomogeneous clouds (relative standard deviation of condensate amount >1). Second, it appears that in ECHAM5, overcast cloud layers occur too frequently and partially cloudy layers too rarely. This problem is not unique to the beta distribution scheme; in fact, it is more pronounced when using an alternative, relative humidity–based cloud fraction scheme.

2021 ◽  
Vol 10 (1) ◽  
pp. 57-64
Author(s):  
Svetlana Galimullovna Denisova ◽  
Antonina Anatolyevna Reut

In introduction studies, it is of great importance to determine how favorable the water balance of the studied species is under given environmental conditions. The aim of the research was to study the water regime of some varieties of chrysanthemums in the conditions of the Southern Ural. The study was conducted in 20182020 on the basis of the South-Ural Botanical Garden-Institute of the Ufa Federal Research Centre of Russian Academy of Sciences. The objects of the study were 23 varieties of Chrysanthemum hortorum Bailey. In the course of the research, the total water content, water-holding capacity, the content of mobile moisture, water deficit, and sublethal water deficit were determined. The analysis of water regime indicators is based on the method of artificial wilting (V.N. Tarenkov, L.N. Ivanova) and the method of saturation of plant samples (V.P. Moiseev, N.P. Reshetsky). Sublethal water deficit was determined by the method of T.K. Goryshina, L.I. Samsonova, modified by N.I. Bobrovskaya. The calculations were carried out by standard methods using statistical packages of the Microsoft Excel 2003 and the Agros 2.13 program. The studies made it possible to determine the value of the sublethal water deficit (28,4%) for the varieties of chrysanthemums in the conditions of the Bashkir Ural. It was found that the studied varieties during the growing season did not experience such a moisture deficit in the tissues that could lead to irreversible damage to the assimilating organs. Our experiments showed that chrysanthemum varieties in the Bashkir Cis-Ural under the same soil-climatic and agrotechnical conditions had the following range of indicators of total water content 70,090,4% and water-holding capacity 19,0064,6%. The analysis of variance revealed significant differences between water-holding capacity and the content of mobile moisture by varieties, the share of influence was 27,8531,71%. As a result of the correlation-regression analysis, the authors revealed a direct dependence of the indicators of mobile moisture content on the total water content, and an inverse one on the indicators of the content of mobile moisture and water-holding capacity.


Talanta ◽  
2006 ◽  
Vol 70 (5) ◽  
pp. 1006-1010 ◽  
Author(s):  
Sébastien N. Ronkart ◽  
Michel Paquot ◽  
Christian Fougnies ◽  
Claude Deroanne ◽  
Jean-Claude Van Herck ◽  
...  

1982 ◽  
Vol 243 (3) ◽  
pp. R271-R280 ◽  
Author(s):  
G. Sjogaard ◽  
B. Saltin

A method was established to analyze the extracellular water space (H2Oe) in small muscle tissue samples as [3H]inulin distribution space. After initial experiments on rats, the method was applied on 13 men and 6 women. Muscles with different fiber compositions (soleus, S; vastus lateralis, (VL; gastrocnemius, G; triceps brachii, TB) were studied at rest. The total water content was the same for all muscles, 320 (313-330) ml/100 g dry wt. However, differences were demonstrated for H2Oe, with 26-34 ml/100 g dry wt in VL and 38-54 ml/100 g dry wt in S, (P less than 0.05); the values for G and TB were in between those for VL and S. The differences in H2Oe were not related to the fiber composition of the muscles. During 3 x 3 min of intense bicycle exercise demanding about 120% VO2 max (6 men), total water content increased in VL from 313 to 359 ml/100 g dry wt and H2Oe increased from 34 to 60 ml/100 g dry wt (P less than 0.05), In TB, which is relatively inactive during bicycle exercise, no such changes occurred. The calculated intracellular lactate concentration increased in VL from 5.7 to 30.6 mmol/l H2Oi. The extracellular lactate concentration amounted to 13.6 mmol/l H2Oe at the end of exercise. The concentration gradient for lactate of 2 from intra- to extracellular space favored a flux of water to the intracellular space. The relative large increase in H2Oe may then be caused by a hydrostatic rather than an osmotic factor.U


1952 ◽  
Vol 8 (2) ◽  
pp. 179-186
Author(s):  
D. F. COLE

The chemical composition of the liver and skeletal muscle in rats which had been treated with 1·0 μg. oestradiol has been investigated. The water and electrolyte content, creatine and creatinine phosphorus fractions and total nucleoproteins were studied. The changes in the water content are reciprocal to those already described for the uterus. The creatine and creatinine content and the total nucleic acid do not change significantly. There is an increase of the acid-soluble phosphorus in the first phase of the water increase in skeletal muscle which is related to some of the changes of intracellular potassium. In the liver there is an increase of the total water content between 28 and 36 hr. after injection, which is also associated with changes of acid-soluble phosphorus and cell electrolytes.


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