scholarly journals A hybrid model for simulating rogue waves in random seas on a large temporal and spatial scale

2016 ◽  
Vol 313 ◽  
pp. 279-309 ◽  
Author(s):  
Jinghua Wang ◽  
Q.W. Ma ◽  
S. Yan
Keyword(s):  
Spatial Scale ◽  
Hybrid Model ◽  
Rogue Waves ◽  
Random Seas ◽  
Temporal And Spatial

scholarly journals 8-Day and Daily Maximum and Minimum Air Temperature Estimation via Machine Learning Method on a Climate Zone to Global Scale

2021 ◽  
Vol 13 (12) ◽  
pp. 2355
Author(s):  
Linglin Zeng ◽  
Yuchao Hu ◽  
Rui Wang ◽  
Xiang Zhang ◽  
Guozhang Peng ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Air Temperature ◽  
Spatial Scales ◽  
Model Performance ◽  
Global Scale ◽  
Scale Model ◽  
Validation Dataset ◽  
Daily Maximum ◽  
Climate Zone ◽  
Temporal And Spatial

Air temperature (Ta) is a required input in a wide range of applications, e.g., agriculture. Land Surface Temperature (LST) products from Moderate Resolution Imaging Spectroradiometer (MODIS) are widely used to estimate Ta. Previous studies of these products in Ta estimation, however, were generally applied in small areas and with a small number of meteorological stations. This study designed both temporal and spatial experiments to estimate 8-day and daily maximum and minimum Ta (Tmax and Tmin) on three spatial scales: climate zone, continental and global scales from 2009 to 2018, using the Random Forest (RF) method based on MODIS LST products and other auxiliary data. Factors contributing to the relation between LST and Ta were determined based on physical models and equations. Temporal and spatial experiments were defined by the rules of dividing the training and validation datasets for the RF method, in which the stations selected in the training dataset were all included or not in the validation dataset. The RF model was first trained and validated on each spatial scale, respectively. On a global scale, model accuracy with a determination coefficient (R2) > 0.96 and root mean square error (RMSE) < 1.96 °C and R2 > 0.95 and RMSE < 2.55 °C was achieved for 8-day and daily Ta estimations, respectively, in both temporal and spatial experiments. Then the model was trained and cross-validated on each spatial scale. The results showed that the data size and station distribution of the study area were the main factors influencing the model performance at different spatial scales. Finally, the spatial patterns of the model performance and variable importance were analyzed. Both daytime and nighttime LST had a significant contribution in the 8-day Tmax estimation on all the three spatial scales; while their contribution in daily Tmax estimation varied over different continents or climate zones. This study was expected to improve our understanding of Ta estimation in terms of accuracy variations and influencing variables on different spatial and temporal scales. The future work mainly includes identifying underlying mechanisms of estimation errors and the uncertainty sources of Ta estimation from a local to a global scale.

A Numerical Study on the Evolution of Random Seas With the Occurrence of Rogue Waves

2021 ◽  
Author(s):  
Zhuowei Zhou ◽  
Ningchuan Zhang ◽  
Guoxing Huang
Keyword(s):  
Numerical Study ◽  
Rogue Waves ◽  
Random Seas

scholarly journals Characteristics of Climate Change and Extreme Weather from 1951 to 2011 in China

2018 ◽  
Vol 15 (11) ◽  
pp. 2540 ◽  
Author(s):  
Chunli Zhao ◽  
Jianguo Chen ◽  
Peng Du ◽  
Hongyong Yuan
Keyword(s):  
Climate Change ◽  
Spatial Scale ◽  
Spatial Scales ◽  
Seasonal Fluctuation ◽  
Extreme Weather ◽  
Temperature And Precipitation ◽  
Weather Variation ◽  
Variation Characteristics ◽  
Established Fact ◽  
Temporal And Spatial

It has been demonstrated that climate change is an established fact. A good comprehension of climate and extreme weather variation characteristics on a temporal and a spatial scale is important for adaptation and response. In this work, the characteristics of temperature, precipitation, and extreme weather distribution and variation is summarized for a period of 60 years and the seasonal fluctuation of temperature and precipitation is also analyzed. The results illustrate the reduction in daily and annual temperature divergence on both temporal and spatial scales. However, the gaps remain relatively significant. Furthermore, the disparity in daily and annual precipitation are found to be increasing on both temporal and spatial scales. The findings indicate that climate change, to a certain extent, narrowed the temperature gap while widening the precipitation gap on temporal and spatial scales in China.

scholarly journals Breather Rogue Waves in Random Seas

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
J. Wang ◽  
Q. W. Ma ◽  
S. Yan ◽  
A. Chabchoub
Keyword(s):  
Rogue Waves ◽  
Random Seas

scholarly journals Localized fast flow disturbance observed in the plasma sheet and in the ionosphere

2005 ◽  
Vol 23 (2) ◽  
pp. 553-566 ◽  
Author(s):  
R. Nakamura ◽  
O. Amm ◽  
H. Laakso ◽  
N. C. Draper ◽  
M. Lester ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Current Sheet ◽  
Plasma Sheet ◽  
Time Scale ◽  
Ionospheric Disturbance ◽  
Flow Shear ◽  
Current Location ◽  
Field Aligned Current ◽  
Temporal And Spatial ◽  
Fast Flow

Abstract. An isolated plasma sheet flow burst took place at 22:02 UT, 1 September 2002, when the Cluster footpoint was located within the area covered by the Magnetometers-Ionospheric Radars-All-sky Cameras Large Experiment (MIRACLE). The event was associated with a clear but weak ionospheric disturbance and took place during a steady southward IMF interval, about 1h preceding a major substorm onset. Multipoint observations, both in space and from the ground, allow us to discuss the temporal and spatial scale of the disturbance both in the magnetosphere and ionosphere. Based on measurements from four Cluster spacecraft it is inferred that Cluster observed the dusk side part of a localized flow channel in the plasma sheet with a flow shear at the front, suggesting a field-aligned current out from the ionosphere. In the ionosphere the equivalent current pattern and possible field-aligned current location show a pattern similar to the auroral streamers previously obtained during an active period, except for its spatial scale and amplitude. It is inferred that the footpoint of Cluster was located in the region of an upward field-aligned current, consistent with the magnetospheric observations. The entire disturbance in the ionosphere lasted about 10min, consistent with the time scale of the current sheet disturbance in the magnetosphere. The plasma sheet bulk flow, on the other hand, had a time scale of about 2min, corresponding to the time scale of an equatorward excursion of the enhanced electrojet. These observations confirm that localized enhanced convection in the magnetosphere and associated changes in the current sheet structure produce a signature with consistent temporal and spatial scale at the conjugate ionosphere.

scholarly journals The archaeology of the longue durée: temporal and spatial scale in the evolution of social complexity on the southern Northwest Coast

Antiquity ◽  
1991 ◽  
Vol 65 (249) ◽  
pp. 935-945 ◽  
Author(s):  
Kenneth M. Ames
Keyword(s):  
Spatial Scale ◽  
Social Complexity ◽  
Northwest Coast ◽  
Short Term ◽  
Geographic Scale ◽  
Medium Length ◽  
Longue Duree ◽  
Longue Durée ◽  
Temporal And Spatial ◽  
Historical Developments

The emphasis on temporal and geographic scale of the French Annales school of history (cf. Braudel 1980; Baker 1984; Lewthwaite 1988) is the inspiration for this paper. Braudel (1980) divides time into three durations: short term events (days, weeks, months, a few years), medium length conjunctures (years, decades, even major portions of centuries), and longterm structures (which may last centuries, even millennia). This last duration is the longue durée. Basic to Annales’ thought – and the longue durée – is the idea that to understand historical developments, to explain their causes and dynamics, one must know their temporal and their geographic scale; one must know what happened at their edges and their centre, why they developed and why they passed away; and how they changed during their span. To do this, since we cannot assume we know the scales relevant to the phenomena which interest us (Braudel 1980), we must continually play different temporal and geographic scales off against each other.

scholarly journals The Impact of Metaphor on G.G. Byron’s Linguopoetic Thinking

2020 ◽  
Vol 16 (1 (21)) ◽  
pp. 90-97
Author(s):  
Varduhi Ghumashyan
Keyword(s):  
Spatial Scale ◽  
Methods Of Analysis ◽  
Musical Perception ◽  
Temporal And Spatial ◽  
The Impact ◽  
Literary Devices

The issue touched upon in this article refers to the extraordinary use of innumerable metaphors in one of the greatest works by George Gordon Byron – Childe Harold’s Pilgrimage. Among literary devices it is especially metaphor that is peculiar to Byron’s linguopoetic thinking. The linguostylistic and linguopoetic methods of analysis help to bring out metaphor as an important device for Byron. Through metaphors he portrays his heroes, their feelings and thoughts and makes the reader feel his powerful flight of imagination. The author does not convince the reader to make the resulting points, but he makes him/her indirectly judge the heroes and understand situations. Thus, Byron’s metaphors are the result of his linguopoetic thinking. They give a certain charm and musical perception through plain words and word-combinations, and serve as a bridge between physics and poetics across temporal and spatial scale.

Sign in / Sign up

Export Citation Format

Share Document