The 3D Structure of Atmospheric Blocking: Role of Moisture and Response to Climate Change

2021 ◽  
Author(s):  
Ebrahim Nabizadeh ◽  
Sandro Lubis ◽  
Pedram Hassanzadeh
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Northern Hemisphere ◽  
Large Scale ◽  
3D Structure ◽  
Winter Season ◽  
Temperature Response ◽  
Atmospheric Blocking ◽  
Weather Extremes ◽  
Large Ensemble

<p>Atmospheric blocking is a large-scale weather phenomenon that interrupts the prevailing eastward progression of pressure systems and can result in weather extremes in the midlatitudes. Due to their devastating consequences, understanding the changes of blocking in response to climate change has been of great interest in recent years. In this study, we investigate the 3D structure of blocking events in reanalysis and two large-ensemble, fully coupled GCM simulations: NCAR’s CESM1 Large-Ensemble Project (LENS) and GFDL-CM3 large-ensemble project. Here we compare the climatology of blocks in the models with reanalysis and show that the structure of the blocks is remarkably reproduced well in the GCMs, given that these models are known to have biases in reproducing the climatological Northern Hemisphere large-scale circulation. The results of our composite analysis indicate that the blocks exhibit an equivalent-barotropic structure in both summer and winter seasons over both oceans and continents in the northern hemisphere. However, blocking events are stronger in winters compared to summers. We also notice a significant latent heating associated with ascending airstream on the east side of blocks. This warming, which is stronger in winter especially over the ocean basins, leads to a westward shift in the temperature anomaly during blocking episodes. Furthermore, we study the response of the blocks to climate change (RCP8.5) and find that blocking events will be weakened in the summer of three different northern hemisphere regions. However, wintertime blocks’ responses to climate change are more complex than those in summers and depend on the regions and atmospheric pressure levels. Finally, we examined the response of surface temperature associated with blocking events. We have found that the surface temperature response associated with blocking events will be weaker over all the regions in the winter season. However, during summer, the temperature responses will be slightly stronger over Russia and partially over the two ocean basins. Our results suggest that summertime blocking events over Russia are going to be more impactful compared to those over the ocean basins.</p>

scholarly journals The Predictability of Blocking Character in the Northern Hemisphere Using an Ensemble Forecast System

2019 ◽  
Vol 13 (1) ◽  
pp. 13-28 ◽  
Author(s):  
DeVondria D. Reynolds ◽  
Anthony R. Lupo ◽  
Andrew D. Jensen ◽  
Patrick S. Market
Keyword(s):  
Northern Hemisphere ◽  
Large Scale ◽  
Weather Conditions ◽  
Atmospheric Blocking ◽  
Weather Extremes ◽  
University Of Missouri ◽  
Weather Patterns ◽  
Temperature And Precipitation ◽  
Environmental Prediction ◽  
The University

Introduction: Some weather extremes are the result of atmospheric blocking, which can be responsible for the stagnation of weather patterns. These large-scale quasi-stationary mid-latitude flow regimes can result in significant temperature and precipitation anomalies over the regions that the blocking event impacts or in the upstream and downstream regions. Methods: The ability to predict periods of anomalous weather conditions due to atmospheric blocking is a major problem for medium-range forecasting. Analyzing the National Centers for Environmental Prediction (NCEP) Ensemble 500-hPa pressure level heights (240 hrs.) ten-day forecasts, and using the University of Missouri blocking archive to identify blocking events, the forecasted onset, duration, and intensity of model blocking events are compared to observed blocks. Results and Discussion: The observed blocking events were identified using the University of Missouri blocking archive. Comparing these differences using four Northern Hemisphere case studies occurring over a one-year period across the Northern Hemisphere has shown the continued need for improvement in the duration and intensity of blocking events. Additionally, a comparison of the block intensity to a diagnostic known as the Integrated Regional Enstrophy (IRE) was performed in order to determine if there is a correlation between IRE and these quantities. Conclusion: Having a better understanding of block persistence and their associated anomalies can help society prepare for the damage they can cause.

scholarly journals Co-occurrence of extreme ozone and heat waves in two cities from Morocco

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Kenza KHOMSI 1,2 ◽  
Houda NAJMI 2 ◽  
Zineb SOUHAILI 1
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Extreme Events ◽  
Global Climate Change ◽  
Large Scale ◽  
Heat Waves ◽  
Global Climate ◽  
Meteorological Factor ◽  
Two Cities ◽  
Change Context

Temperature is the first meteorological factor to be directly involved in leading ozone (O3) extreme events. Generally, upward temperatures increase the probability of having exceedance in ozone adopted thresholds. In the global climate change context more frequent and/or persistent heat waves and extreme ozone (O3) episodes are likely to occur during in coming decades and a key question is about the coincidence and co-occurrence of these extremes. In this paper, using 7 years of surface temperature and air quality observations over two cities from Morocco (Casablanca and Marrakech) and implementing a percentile thresholding approach, we show that the extremes in temperature and ozone (O3) cluster together in many cases and that the outbreak of ozone events generally match the first or second days of heat waves. This co-occurrence of extreme episodes is highly impacted by humidity and may be overlapping large-scale episodes.

scholarly journals Statistical Downscaling Forecasts for Winter Monsoon Precipitation in Malaysia Using Multimodel Output Variables

2010 ◽  
Vol 23 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Liew Juneng ◽  
Fredolin T. Tangang ◽  
Hongwen Kang ◽  
Woo-Jin Lee ◽  
Yap Kok Seng
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Statistical Downscaling ◽  
Large Scale ◽  
Winter Season ◽  
Peninsular Malaysia ◽  
Sea Surface ◽  
Asia Pacific ◽  
Forecast Data ◽  
Multimodel Ensembles

Abstract This paper compares the skills of four different forecasting approaches in predicting the 1-month lead time of the Malaysian winter season precipitation. Two of the approaches are based on statistical downscaling techniques of multimodel ensembles (MME). The third one is the ensemble of raw GCM forecast without any downscaling, whereas the fourth approach, which provides a baseline comparison, is a purely statistical forecast based solely on the preceding sea surface temperature anomaly. The first multimodel statistical downscaling method was developed by the Asia-Pacific Economic Cooperation (APEC) Climate Center (APCC) team, whereas the second is based on the canonical correlation analysis (CCA) technique using the same predictor variables. For the multimodel downscaling ensemble, eight variables from seven operational GCMs are used as predictors with the hindcast forecast data spanning a period of 21 yr from 1983/84 to 2003/04. The raw GCM forecast ensemble tends to have higher skills than the baseline skills of the purely statistical forecast that relates the dominant modes of observed sea surface temperature variability to precipitation. However, the downscaled MME forecasts have higher skills than the raw GCM products. In particular, the model developed by APCC showed significant improvement over the peninsular Malaysia region. This is attributed to the model’s ability to capture regional and large-scale predictor signatures from which the additional skills originated. Overall, the results showed that the appropriate downscaling technique and ensemble of various GCM forecasts could result in some skill enhancement, particularly over peninsular Malaysia, where other models tend to have lower or no skills.

scholarly journals Evaluation of a unique approach to high-resolution climate modeling using the Model for Prediction Across Scales – Atmosphere (MPAS-A) version 5.1

2019 ◽  
Vol 12 (8) ◽  
pp. 3725-3743 ◽  
Author(s):  
Allison C. Michaelis ◽  
Gary M. Lackmann ◽  
Walter A. Robinson
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Sea Ice ◽  
Northern Hemisphere ◽  
General Circulation ◽  
Large Scale ◽  
Southern Oscillation ◽  
Spatial Scales ◽  
Coupled Model ◽  
General Circulation Models

Abstract. We present multi-seasonal simulations representative of present-day and future environments using the global Model for Prediction Across Scales – Atmosphere (MPAS-A) version 5.1 with high resolution (15 km) throughout the Northern Hemisphere. We select 10 simulation years with varying phases of El Niño–Southern Oscillation (ENSO) and integrate each for 14.5 months. We use analyzed sea surface temperature (SST) patterns for present-day simulations. For the future climate simulations, we alter present-day SSTs by applying monthly-averaged temperature changes derived from a 20-member ensemble of Coupled Model Intercomparison Project phase 5 (CMIP5) general circulation models (GCMs) following the Representative Concentration Pathway (RCP) 8.5 emissions scenario. Daily sea ice fields, obtained from the monthly-averaged CMIP5 ensemble mean sea ice, are used for present-day and future simulations. The present-day simulations provide a reasonable reproduction of large-scale atmospheric features in the Northern Hemisphere such as the wintertime midlatitude storm tracks, upper-tropospheric jets, and maritime sea-level pressure features as well as annual precipitation patterns across the tropics. The simulations also adequately represent tropical cyclone (TC) characteristics such as strength, spatial distribution, and seasonal cycles for most Northern Hemisphere basins. These results demonstrate the applicability of these model simulations for future studies examining climate change effects on various Northern Hemisphere phenomena, and, more generally, the utility of MPAS-A for studying climate change at spatial scales generally unachievable in GCMs.

scholarly journals Impacts of regional climate and teleconnection on hydrological change in the Bosten Lake Basin, arid region of northwestern China

2017 ◽  
Vol 9 (1) ◽  
pp. 74-88 ◽  
Author(s):  
Huaijun Wang ◽  
Yingping Pan ◽  
Yaning Chen
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Large Scale ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Circulation Index ◽  
Lake Basin ◽  
Area Index ◽  
Bosten Lake

Abstract This investigation examined effects of climate change, measured as annual, seasonal, and monthly air temperature and precipitation from 1958 to 2010, on water resources (i.e., runoff) in the Bosten Lake Basin. Additionally, teleconnections of hydrological changes to large-scale circulation indices including El Nino Southern Oscillation (ENSO), Arctic Oscillation (AO), North Atlantic Oscillation (NAO), Tibetan High (XZH), westerly circulation index (WI), and northern hemisphere polar vortex area index (VPA) were analyzed in our study. The results showed the following. (1) Annual and seasonal air temperature increased significantly in the Bosten Lake Basin. Precipitation exhibited an increasing trend, while the significance was less than that of temperature. Abrupt changes were observed in 1996 in mountain temperature and in 1985 in plain temperature. (2) Runoff varied in three stages, decreasing before 1986, increasing from 1987 to 2003, and decreasing after 2003. (3) Precipitation and air temperature have significant impacts on runoff. The hydrological processes in the Bosten Lake Basin were (statistically) significantly affected by the northern hemisphere polar vortex area index (VPA) and the Tibetan High (XZH). The results of this study are good indicators of local climate change, which can enhance human mitigation of climate warming in the Bosten Lake Basin.

scholarly journals Avaliação da variação da temperatura superficial na lagoa rasa de Itapeva mediante a imagens de satélite

2020 ◽  
Vol 42 ◽  
pp. e103
Author(s):  
Itzayana Gonzalez Avila ◽  
Alfonso Risso ◽  
Mauricio Andrades Paixão
Keyword(s):  
Surface Temperature ◽  
Water Temperature ◽  
Satellite Images ◽  
Winter Season ◽  
Temperature Response ◽  
Original Data ◽  
Spatial And Temporal Variability ◽  
Variation Pattern ◽  
Surface Temperature Variation

The role of temperature in water is fundamental for the community aquatic dynamics once it regulates several processes on different scales. The spatial and temporal variability of water temperature can be assessed by satellite images, which allows a better understanding of ecosystems. In this work, we evaluated the surface temperature variation of Itapeva Lake, located in Rio Grande do Sul, Brazil, between 1985 and 2017, using MOD11A1 product and images Landsat 5, 7 and 8. An homogeneous seasonal variation pattern was identify between the two sensors used. The information provided by MODIS and Landsat has a coefficient R2 = 0.91 and RMSE = 2.32 ° C. The analysis between the Landsat series adjusted data and the original data allowed the smoothing of maximum and minimum temperatures of water, reducing biased records. Water temperature for the summer and autumn months increases, while for the winter season the regime decrease. However, the surface temperature response may be better understood by involving climatic variables in the study.

scholarly journals Global Mean Surface Temperature Response to Large‐Scale Patterns of Variability in Observations and CMIP5

2019 ◽  
Vol 46 (4) ◽  
pp. 2232-2241 ◽  
Author(s):  
Jules B. Kajtar ◽  
Matthew Collins ◽  
Leela M. Frankcombe ◽  
Matthew H. England ◽  
Timothy J. Osborn ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Large Scale ◽  
Temperature Response ◽  
Global Mean Surface Temperature ◽  
Global Mean

Temperature Rising (Two Celsius) Effect on Planktonic Biomass in Subtropical Marshes, Iraq

2021 ◽  
Vol 5 (1) ◽  
pp. 44-52
Author(s):  
Mohammed Al-Haidarey
Keyword(s):  
Climate Change ◽  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Winter Season ◽  
Heating System ◽  
Early Spring ◽  
Natural Sediment ◽  
Lake Ecosystems

Planktonic species may respond to climate change through their niche across three axes which include self, space and time. This study was designed to investigate the effect of increasing winter temperature on the plankton biomass, the mesocosm was constructed as a collection of 16 enclosures with a water-outlet system and natural sediment, two aquatic plant species and heating system. This research was conducted over 12 weeks (beginning on Dec. 2018) when the temperature of eight enclosures was 2±0.2 °C higher than the ambient temperature. Weekly abiotic parameters (salinity, pH, PO4, NO3, DIC) and biotic (chlorophyll-a, zooplankton and phytoplankton biomass) were reported. The obtained results showed that there were no major improvements in salinity, pH, PO4, NO3 and dissolved inorganic carbon (DIC). Whereas, chlorophyll-a, zooplankton and phytoplankton biomass have dramatically improved. Therefore, this research has indicated that water temperature change during the winter season due to climate change could affect planktonic biomass and early spring in subtropical marshes, but this study was performed in the mesocosm experiment and it needs to be studied in large-scale natural lake ecosystems.

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