scholarly journals Rainfall variations induced by the lunar gravitational atmospheric tide and their implications for the relationship between tropical rainfall and humidity

2016 ◽  
Vol 43 (2) ◽  
pp. 918-923 ◽  
Author(s):  
Tsubasa Kohyama ◽  
John M. Wallace
Keyword(s):  
Atmospheric Tide ◽  
Tropical Rainfall ◽  
Rainfall Variations ◽  
The Relationship

scholarly journals Rainfall variations in central Indo-Pacific over the past 2,700 y

2019 ◽  
Vol 116 (35) ◽  
pp. 17201-17206 ◽  
Author(s):  
Liangcheng Tan ◽  
Chuan-Chou Shen ◽  
Ludvig Löwemark ◽  
Sakonvan Chawchai ◽  
R. Lawrence Edwards ◽  
...  
Keyword(s):  
Rainfall Variability ◽  
Walker Circulation ◽  
Warm Period ◽  
Tropical Rainfall ◽  
The Past ◽  
Decadal Scale ◽  
Continuous Record ◽  
Southern Central ◽  
Drying Trend ◽  
Rainfall Variations

Tropical rainfall variability is closely linked to meridional shifts of the Intertropical Convergence Zone (ITCZ) and zonal movements of the Walker circulation. The characteristics and mechanisms of tropical rainfall variations on centennial to decadal scales are, however, still unclear. Here, we reconstruct a replicated stalagmite-based 2,700-y-long, continuous record of rainfall for the deeply convective northern central Indo-Pacific (NCIP) region. Our record reveals decreasing rainfall in the NCIP over the past 2,700 y, similar to other records from the northern tropics. Notable centennial- to decadal-scale dry climate episodes occurred in both the NCIP and the southern central Indo-Pacific (SCIP) during the 20th century [Current Warm Period (CWP)] and the Medieval Warm Period (MWP), resembling enhanced El Niño-like conditions. Further, we developed a 2,000-y-long ITCZ shift index record that supports an overall southward ITCZ shift in the central Indo-Pacific and indicates southward mean ITCZ positions during the early MWP and the CWP. As a result, the drying trend since the 20th century in the northern tropics is similar to that observed during the past warm period, suggesting that a possible anthropogenic forcing of rainfall remains indistinguishable from natural variability.

scholarly journals Excitation Mechanisms of the Teleconnection Patterns Affecting the July Precipitation in Northwest China

2012 ◽  
Vol 25 (22) ◽  
pp. 7834-7851 ◽  
Author(s):  
Guosen Chen ◽  
Ronghui Huang
Keyword(s):  
Northwest China ◽  
Silk Road ◽  
Central Pacific ◽  
Tropical Rainfall ◽  
Teleconnection Patterns ◽  
Excitation Mechanisms ◽  
Silk Road Pattern ◽  
Rainfall Variations ◽  
The Silk Road ◽  
Tropical Heating

Abstract Using observational rainfall data and atmospheric reanalysis data, the precipitation variations in Northwest China during July and the corresponding atmospheric teleconnection patterns are studied. The results indicate that the leading modes of July precipitation variations in Northwest China are affected by the Silk Road pattern and the Europe–China (EC) pattern. The analysis suggests that the circumglobal teleconnection (CGT) could be considered as the interannual component of the Silk Road pattern. To investigate the excitation mechanisms for the CGT pattern and EC pattern on interannual time scales, the singular value decomposition (SVD) analysis is performed between 200-hPa meridional wind velocity over the region of (30°–60°N, 30°–130°E) and tropical rainfall between (15°S and 30°N). The results suggest that the tropical heating anomalies most responsible for the CGT pattern are located over the North Indian Ocean, and the tropical heating anomalies most responsible for EC pattern are located over equatorial central Pacific, Indonesia, and tropical Atlantic. The tropical heating anomalies excite the CGT pattern and EC pattern by inducing divergent flow at the upper troposphere, and the advections of vorticity by the divergent component of the flow act as effective Rossby wave sources. Further analysis indicates that the tropical rainfall anomalies responsible for the CGT pattern and EC pattern are the leading modes of tropical rainfall variations, and these modes of tropical rainfall variations are related to the SST anomalies.

Tropical Rainfall Variability Accompanying Global Normal Mode Oscillations

2021 ◽  
Author(s):  
Takatoshi Sakazaki
Keyword(s):  
Normal Mode ◽  
Amazon Basin ◽  
Rainfall Variability ◽  
Normal Modes ◽  
Low Frequency ◽  
Phase Relationship ◽  
Moisture Flux ◽  
Tropical Rainfall ◽  
Zonal Wavenumber ◽  
Rainfall Variations

AbstractUsing global precipitation datasets (GSMaP, TRMM) and the latest reanalysis data (ERA5) we performed a comprehensive analysis of the tropical rainfall variability that accompanies global-scale, low-frequency normal modes: Rossby, Rossby-gravity and Kelvin modes. Cross spectral analysis and lag-regression analysis both showed that coherent rainfall variations accompany not only the wavenumber 1 gravest Rossby mode (“5 day” wave) but other low-frequency modes. The normal mode rainfall variations are enhanced in regions such as the Amazon basin, but also include circumglobally travelling structures with substantial amplitude over the open ocean. These results are remarkably consistent among the three datasets including even ERA5 rainfall data. The circumglobal rainfall signals may be considered primarily as a response to the normal mode dynamical variations. We found that the phase relationship between rainfall and dynamical field variability is strongly dependent on the type of mode and even on the zonal wavenumber. We suggest that this is explained by the difference in relative importance of two underlying processes: (1) moisture-flux convergence and (2) rainfall enhancement associated with adiabatic cooling. Our determined rainfall signals are the response to quasi-monochromatic, periodic waves that have a simple vertical structure and represent one special case of tropospheric wave-rainfall coupling. Implications for the mechanism of 12-hr rainfall oscillations believed to be forced by the atmospheric tide are also considered.

scholarly journals Indoor monitoring of Scrovegni Chapel Crypt

2019 ◽  
Vol 111 ◽  
pp. 02075
Author(s):  
Paolo Bison ◽  
Alessandro Bortolin ◽  
Gianluca Cadelano ◽  
Giovanni Ferrarini ◽  
Fabio Peron ◽  
...  
Keyword(s):  
Water System ◽  
Building Structures ◽  
Non Invasive ◽  
Scientific Technical ◽  
Rainfall Variations ◽  
Measurement Devices ◽  
Scrovegni Chapel ◽  
The Relationship ◽  
Non Destructive ◽  
Indoor Monitoring

The indoor microclimate of the Scrovegni Chapel in Padova (Italy) was analysed first in the ‘80s. The early study operates in the best way for what concerns the choice of measurement devices and their positioning. Starting from 1995 a Scientific-technical Board coordinates the various initiatives commissioned for the surveys of a conservation of the Scrovegni building structures and for the preservation of frescos. However only during the last ten years, the activities of the Board have been addressed also on the study of the hypogeal environments under the Chapel and in the external environment around it in order to prevent possible damage due to the presence of water which frequently submerges the floor and part of the vertical structures of the crypt (perimeter walls and brick partitions). The investigations have been therefore extended to the crypt. The present work reports the preliminary results of the cyclical survey campaign launched last year and still ongoing: passive thermographic techniques (non-invasive and non-destructive) have been used for the identification and the investigation of the relationship between the boundary seasonal thermohygrometric conditions and the rainfall variations and other exogenous phenomena related to the complex water system of the area on which the Scrovegni Chapel stands.

scholarly journals Flood modelling using satellite-based precipitation estimates and digital elevation model in eastern Iraq

2018 ◽  
Vol 6 (1) ◽  
pp. 72 ◽  
Author(s):  
Zaidoon Abdulrazzaq ◽  
Nadia Aziz ◽  
Abdulkareem Mohammed
Keyword(s):  
Digital Elevation Model ◽  
Rainfall Intensity ◽  
Tropical Rainfall Measuring Mission ◽  
Rain Gauge ◽  
Landsat 8 ◽  
Flood Prediction ◽  
Tropical Rainfall ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Relationship

Increasingly available and a virtually uninterrupted supply of satellite-estimated rainfall data is gradually becoming a cost-effective source of input for flood prediction under a variety of circumstances. The study conducted in Wasit province/Eastern Iraq when a flood occurs due to heavy rainfall in May 2013. In this study the capability of Tropical Rainfall Measuring Mission (TRMM) rainfall daily data have been used to estimate the relationship between measured precipitation and the Digital Elevation Model (DEM), also to study the relationship between rainfall intensity and flood waters areas. Rainfall estimation by remote sensing using satellite-derived data from the Tropical Rainfall Measuring Mission (TRMM) is a possible means of supplementing rain gauge data, having the better spatial cover of rainfall fields. The approach used throughout this paper has integrated recently compiled data derived from satellite imagery (rainfall, and digital elevation model) into a GIS geodatabase to study the relationship between rainfall intensity and floodwater's areas then the results' comparison with the Normalized Difference Water Index (NDWI) after the flood. ArcGIS software has been used to process, analyze the archived Tropical Rainfall Measuring Mission (TRMM) precipitation data, and calculate NDWI from Landsat 8 images. In conclusions, the study explains the flood-area clearly captured by the TRMM measurements; and the region’s water increased. Also, good correlation between measured precipitation and the Digital Elevation Model (DEM) has been detected.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

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