The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform

Manoj Joshi - One of the best experts on this subject based on the ideXlab platform.

  • global response of Clear Air Turbulence to climate change
    Geophysical Research Letters, 2017
    Co-Authors: Luke N. Storer, Paul Williams, Manoj Joshi
    Abstract:

    Clear-Air Turbulence (CAT) is one of the largest causes of weather-related aviation incidents. Here we use climate model simulations to study the impact that climate change could have on global CAT by the period 2050–2080. We extend previous work by analyzing eight geographic regions, two flight levels, five Turbulence strength categories, and four seasons. We find large relative increases in CAT, especially in the midlatitudes in both hemispheres, with some regions experiencing several hundred per cent more Turbulence. The busiest international Airspace experiences the largest increases, with the volume of severe CAT approximately doubling over North America, the North Pacific, and Europe. Over the North Atlantic, severe CAT in future becomes as common as moderate CAT historically. These results highlight the increasing need to improve operational CAT forecasts and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew.

  • Global Response of Clear‐Air Turbulence to Climate Change
    Geophysical Research Letters, 2017
    Co-Authors: Luke N. Storer, Paul D. Williams, Manoj Joshi
    Abstract:

    Clear-Air Turbulence (CAT) is one of the largest causes of weather-related aviation incidents. Here we use climate model simulations to study the impact that climate change could have on global CAT by the period 2050–2080. We extend previous work by analyzing eight geographic regions, two flight levels, five Turbulence strength categories, and four seasons. We find large relative increases in CAT, especially in the midlatitudes in both hemispheres, with some regions experiencing several hundred per cent more Turbulence. The busiest international Airspace experiences the largest increases, with the volume of severe CAT approximately doubling over North America, the North Pacific, and Europe. Over the North Atlantic, severe CAT in future becomes as common as moderate CAT historically. These results highlight the increasing need to improve operational CAT forecasts and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew.

  • Clear-Air Turbulence in a Changing Climate
    Aviation Turbulence, 2016
    Co-Authors: Paul D. Williams, Manoj Joshi
    Abstract:

    How might the processes generating Clear-Air Turbulence change in a warmer world? We know that observations support an association between Clear-Air Turbulence and shear instability. We also know that the upper atmospheric wind shears are changing in response to greenhouse gas forcing. In particular, theoretical reasoning and climate model simulations both suggest that the vertical shear in horizontal wind is increasing in magnitude at typical Aircraft cruising altitudes in the middle latitudes, especially in the winter months in each hemisphere. This increased shearing implies that Clear-Air Turbulence may itself be changing as a consequence of climate change. This chapter reviews the various lines of observational and model-based evidence for trends in Clear-Air Turbulence, by analyzing data from Turbulence encounters with Aircraft, Turbulence diagnosed from reanalysis datasets, passenger injuries caused by Turbulence, and Turbulence diagnosed from climate models. The possibility of anthropogenic trends in Clear-Air Turbulence opens up a whole new field of academic study, which exists at the interface between the two scientific disciplines of aviation Turbulence and climate change. We call for future work to improve our understanding of this poorly understood but potentially important impact of climate change.

Shoichiro Fukao - One of the best experts on this subject based on the ideXlab platform.

  • MU Radar and Lidar Observations of Clear-Air Turbulence underneath Cirrus
    Monthly Weather Review, 2010
    Co-Authors: Hubert Luce, Takuji Nakamura, Masayuki Yamamoto, Mamoru Yamamoto, Shoichiro Fukao
    Abstract:

    Abstract Turbulence generation mechanisms prevalent in the atmosphere are mainly shear instabilities, breaking of internal buoyancy waves, and convective instabilities such as thermal convection due to heating of the ground. In the present work, Clear-Air Turbulence underneath a cirrus cloud base is described owing to coincident observations from the VHF (46.5 MHz) middle and upper atmosphere (MU) radar, a Rayleigh–Mie–Raman (RMR) lidar, and a balloon radiosonde on 7–8 June 2006 (at Shigaraki, Japan; 34.85°N, 136.10°E). Time–height cross section of lidar backscatter ratio obtained at 2206 LT 7 June 2006 showed the presence of a cirrus layer between 8.0 and 12.5 km MSL. Downward-penetrating structures of ice crystals with horizontal and vertical extents of 1.0–4.0 km and 200–800 m, respectively, have been detected at the cirrus cloud base for about 35 min. At the same time, the MU radar data revealed Clear-Air Turbulence layers developing downward from the cloud base in the environment of the protuberances...

Paul D. Williams - One of the best experts on this subject based on the ideXlab platform.

  • Global Response of Clear‐Air Turbulence to Climate Change
    Geophysical Research Letters, 2017
    Co-Authors: Luke N. Storer, Paul D. Williams, Manoj Joshi
    Abstract:

    Clear-Air Turbulence (CAT) is one of the largest causes of weather-related aviation incidents. Here we use climate model simulations to study the impact that climate change could have on global CAT by the period 2050–2080. We extend previous work by analyzing eight geographic regions, two flight levels, five Turbulence strength categories, and four seasons. We find large relative increases in CAT, especially in the midlatitudes in both hemispheres, with some regions experiencing several hundred per cent more Turbulence. The busiest international Airspace experiences the largest increases, with the volume of severe CAT approximately doubling over North America, the North Pacific, and Europe. Over the North Atlantic, severe CAT in future becomes as common as moderate CAT historically. These results highlight the increasing need to improve operational CAT forecasts and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew.

  • Increased light, moderate, and severe Clear-Air Turbulence in response to climate change
    Advances in Atmospheric Sciences, 2017
    Co-Authors: Paul D. Williams
    Abstract:

    Anthropogenic climate change is expected to strengthen the vertical wind shears at Aircraft cruising altitudes within the atmospheric jet streams. Such a strengthening would increase the prevalence of the shear instabilities that generate Clear-Air Turbulence. Climate modelling studies have indicated that the amount of moderate-or-greater Clear-Air Turbulence on transatlantic flight routes in winter will increase significantly in future as the climate changes. However, the individual responses of light, moderate, and severe Clear-Air Turbulence have not previously been studied, despite their importance for Aircraft operations. Here, we use climate model simulations to analyse the transatlantic wintertime Clear-Air Turbulence response to climate change in five aviation-relevant Turbulence strength categories. We find that the probability distributions for an ensemble of 21 Clear-Air Turbulence diagnostics generally gain probability in their right-hand tails when the atmospheric carbon dioxide concentration is doubled. By converting the diagnostics into eddy dissipation rates, we find that the ensembleaverage Airspace volume containing light Clear-Air Turbulence increases by 59% (with an intra-ensemble range of 43%–68%), light-to-moderate by 75% (39%–96%), moderate by 94% (37%–118%), moderate-to-severe by 127% (30%–170%), and severe by 149% (36%–188%). These results suggest that the prevalence of transatlantic wintertime Clear-Air Turbulence will increase significantly in all aviation-relevant strength categories as the climate changes.

  • Clear-Air Turbulence in a Changing Climate
    Aviation Turbulence, 2016
    Co-Authors: Paul D. Williams, Manoj Joshi
    Abstract:

    How might the processes generating Clear-Air Turbulence change in a warmer world? We know that observations support an association between Clear-Air Turbulence and shear instability. We also know that the upper atmospheric wind shears are changing in response to greenhouse gas forcing. In particular, theoretical reasoning and climate model simulations both suggest that the vertical shear in horizontal wind is increasing in magnitude at typical Aircraft cruising altitudes in the middle latitudes, especially in the winter months in each hemisphere. This increased shearing implies that Clear-Air Turbulence may itself be changing as a consequence of climate change. This chapter reviews the various lines of observational and model-based evidence for trends in Clear-Air Turbulence, by analyzing data from Turbulence encounters with Aircraft, Turbulence diagnosed from reanalysis datasets, passenger injuries caused by Turbulence, and Turbulence diagnosed from climate models. The possibility of anthropogenic trends in Clear-Air Turbulence opens up a whole new field of academic study, which exists at the interface between the two scientific disciplines of aviation Turbulence and climate change. We call for future work to improve our understanding of this poorly understood but potentially important impact of climate change.

Luke N. Storer - One of the best experts on this subject based on the ideXlab platform.

  • global response of Clear Air Turbulence to climate change
    Geophysical Research Letters, 2017
    Co-Authors: Luke N. Storer, Paul Williams, Manoj Joshi
    Abstract:

    Clear-Air Turbulence (CAT) is one of the largest causes of weather-related aviation incidents. Here we use climate model simulations to study the impact that climate change could have on global CAT by the period 2050–2080. We extend previous work by analyzing eight geographic regions, two flight levels, five Turbulence strength categories, and four seasons. We find large relative increases in CAT, especially in the midlatitudes in both hemispheres, with some regions experiencing several hundred per cent more Turbulence. The busiest international Airspace experiences the largest increases, with the volume of severe CAT approximately doubling over North America, the North Pacific, and Europe. Over the North Atlantic, severe CAT in future becomes as common as moderate CAT historically. These results highlight the increasing need to improve operational CAT forecasts and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew.

  • Global Response of Clear‐Air Turbulence to Climate Change
    Geophysical Research Letters, 2017
    Co-Authors: Luke N. Storer, Paul D. Williams, Manoj Joshi
    Abstract:

    Clear-Air Turbulence (CAT) is one of the largest causes of weather-related aviation incidents. Here we use climate model simulations to study the impact that climate change could have on global CAT by the period 2050–2080. We extend previous work by analyzing eight geographic regions, two flight levels, five Turbulence strength categories, and four seasons. We find large relative increases in CAT, especially in the midlatitudes in both hemispheres, with some regions experiencing several hundred per cent more Turbulence. The busiest international Airspace experiences the largest increases, with the volume of severe CAT approximately doubling over North America, the North Pacific, and Europe. Over the North Atlantic, severe CAT in future becomes as common as moderate CAT historically. These results highlight the increasing need to improve operational CAT forecasts and to use them effectively in flight planning, to limit discomfort and injuries among passengers and crew.

Christian Werner - One of the best experts on this subject based on the ideXlab platform.