Search Results
. We will first diagnose the local and instantaneous moisture tendency in the direct vicinity of the cloud (a few tens of minutes and a few kilometers) before evaluating the moisture tendency on the mesoscale (a few hours and 10–100 km). Thus, we take advantage of the collocated high-frequency observations of cloud populations by C-band-scanning Doppler radar and lower-tropospheric moisture profiles by a high-spectral-resolution lidar (HSRL) onboard the Research Vessel (R/V) Mirai . For technical
. We will first diagnose the local and instantaneous moisture tendency in the direct vicinity of the cloud (a few tens of minutes and a few kilometers) before evaluating the moisture tendency on the mesoscale (a few hours and 10–100 km). Thus, we take advantage of the collocated high-frequency observations of cloud populations by C-band-scanning Doppler radar and lower-tropospheric moisture profiles by a high-spectral-resolution lidar (HSRL) onboard the Research Vessel (R/V) Mirai . For technical
al. 2000 ). Data from Manus also included observations from a microwave radiometer (MWR), upper-air soundings, a micropulse lidar (MPL), a ceilometer, and optical rain gauges. Other data used are rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM 3B42v7; 0.25° × 0.25°; Kummerow et al. 2000 ); rainfall, specific humidity, and its physical tendency term from the operational analysis (0.56° × 0.56°) of the European Centre for Medium Range Weather Forecasts (ECMWF) prepared for
al. 2000 ). Data from Manus also included observations from a microwave radiometer (MWR), upper-air soundings, a micropulse lidar (MPL), a ceilometer, and optical rain gauges. Other data used are rainfall estimates from the Tropical Rainfall Measuring Mission (TRMM 3B42v7; 0.25° × 0.25°; Kummerow et al. 2000 ); rainfall, specific humidity, and its physical tendency term from the operational analysis (0.56° × 0.56°) of the European Centre for Medium Range Weather Forecasts (ECMWF) prepared for
1. Introduction During the Dynamics of the Madden–Julian Oscillation (DYNAMO) 1 field campaign ( Yoneyama et al. 2013 ), two quadrilateral sounding arrays were formed with six sites (two ships and four islands) over the equatorial central Indian Ocean ( Fig. 1 ). Intensive sounding observations (eight per day) were taken during the special observing period (SOP) of 1 October–15 December 2011 from the arrays, which were reduced to triangles for short periods of ship port calls and after the SOP
1. Introduction During the Dynamics of the Madden–Julian Oscillation (DYNAMO) 1 field campaign ( Yoneyama et al. 2013 ), two quadrilateral sounding arrays were formed with six sites (two ships and four islands) over the equatorial central Indian Ocean ( Fig. 1 ). Intensive sounding observations (eight per day) were taken during the special observing period (SOP) of 1 October–15 December 2011 from the arrays, which were reduced to triangles for short periods of ship port calls and after the SOP
surface rainfall as well as observed top-of-atmosphere and surface radiation based on the method developed by Zhang et al. (2001) . Three versions of the forcing data using the above-mentioned precipitation products are used to account for uncertainties in the rainfall estimates. The forcing dataset is used as a proxy for observations in this study rather than to drive model simulations (as they are commonly used). The length of the forcing time series is 90 days (1 October–31 December 2011). The
surface rainfall as well as observed top-of-atmosphere and surface radiation based on the method developed by Zhang et al. (2001) . Three versions of the forcing data using the above-mentioned precipitation products are used to account for uncertainties in the rainfall estimates. The forcing dataset is used as a proxy for observations in this study rather than to drive model simulations (as they are commonly used). The length of the forcing time series is 90 days (1 October–31 December 2011). The
A field campaign in the Indian Ocean region collected unprecedented observations during October 2011–March 2012 to help advance knowledge of physical processes of the MJO—especially its convective initiation—and improve its prediction. View from Addu Atoll showing a mix of convective and cirroform clouds. From time to time, the tropical atmosphere feels the pulses of extraordinary strong deep convection and rainfall that repeat every 30–90 days. They come from the Madden–Julian oscillation (MJO
A field campaign in the Indian Ocean region collected unprecedented observations during October 2011–March 2012 to help advance knowledge of physical processes of the MJO—especially its convective initiation—and improve its prediction. View from Addu Atoll showing a mix of convective and cirroform clouds. From time to time, the tropical atmosphere feels the pulses of extraordinary strong deep convection and rainfall that repeat every 30–90 days. They come from the Madden–Julian oscillation (MJO
obtain the best-estimate time–height fields of the three radar moments (i.e., reflectivity, Doppler velocity, and spectral width). The KAZR-ARSCL product has vertical and temporal resolution of 30 m and 4 s, respectively. Although KAZR-ARSCL provides cloud boundaries that are derived from a combination of KAZR measurements and observations from the micropulse lidar and ceilometer, they are not used for comparison purpose in this study because reflectivity measurements from S-Pol and SMART-R are
obtain the best-estimate time–height fields of the three radar moments (i.e., reflectivity, Doppler velocity, and spectral width). The KAZR-ARSCL product has vertical and temporal resolution of 30 m and 4 s, respectively. Although KAZR-ARSCL provides cloud boundaries that are derived from a combination of KAZR measurements and observations from the micropulse lidar and ceilometer, they are not used for comparison purpose in this study because reflectivity measurements from S-Pol and SMART-R are
radiometer possesses 21 channels between 22 and 30 GHz, sampling along different positions on the pressure-broadened 22.235-GHz H 2 O absorption line. The utilized zenith-pointing scans are embedded within a scanning pattern set to match that of a collocated S-PolKa radar ( Sahoo et al. 2015 ), and as such had irregular time stamps, but with data available every minute. The radiometer maintains its calibration through an automated routine, whereby observations are gathered at a range of airmass opacities
radiometer possesses 21 channels between 22 and 30 GHz, sampling along different positions on the pressure-broadened 22.235-GHz H 2 O absorption line. The utilized zenith-pointing scans are embedded within a scanning pattern set to match that of a collocated S-PolKa radar ( Sahoo et al. 2015 ), and as such had irregular time stamps, but with data available every minute. The radiometer maintains its calibration through an automated routine, whereby observations are gathered at a range of airmass opacities
15 W m −2 are shown with a contour interval of 3 W m −2 , yellow contour is 21 W m −2 ]. (b) Zonal wind stress (shaded) and wind stress vectors from SCOW. The zero zonal wind stress contour is gray. The standard deviation of intraseasonal zonal wind stress is contoured at 0.015 (dashed), 0.02 (light), and 0.025 (thick) N m −2 . Locations of DYNAMO (80.5°E) and TOGA COARE (156°E) ship observations used in this paper are marked with yellow stars. Three MJO convective events and their accompanying
15 W m −2 are shown with a contour interval of 3 W m −2 , yellow contour is 21 W m −2 ]. (b) Zonal wind stress (shaded) and wind stress vectors from SCOW. The zero zonal wind stress contour is gray. The standard deviation of intraseasonal zonal wind stress is contoured at 0.015 (dashed), 0.02 (light), and 0.025 (thick) N m −2 . Locations of DYNAMO (80.5°E) and TOGA COARE (156°E) ship observations used in this paper are marked with yellow stars. Three MJO convective events and their accompanying
. Fukao , F. Dalaudier , and M. Crochet , 2002 : Strong mixing events observed near the tropopause with the MU radar and high-resolution balloon techniques . J. Atmos. Sci. , 59 , 2885 – 2896 , doi: 10.1175/1520-0469(2002)059<2885:SMEONT>2.0.CO;2 . 10.1175/1520-0469(2002)059<2885:SMEONT>2.0.CO;2 Luce , H. , T. Takai , T. Nakamura , M. Yamamoto , and S. Fukao , 2010a : Simultaneous observations of thin humidity gradients in the lower troposphere with a Raman lidar and the very
. Fukao , F. Dalaudier , and M. Crochet , 2002 : Strong mixing events observed near the tropopause with the MU radar and high-resolution balloon techniques . J. Atmos. Sci. , 59 , 2885 – 2896 , doi: 10.1175/1520-0469(2002)059<2885:SMEONT>2.0.CO;2 . 10.1175/1520-0469(2002)059<2885:SMEONT>2.0.CO;2 Luce , H. , T. Takai , T. Nakamura , M. Yamamoto , and S. Fukao , 2010a : Simultaneous observations of thin humidity gradients in the lower troposphere with a Raman lidar and the very
soundings (eight per day) of velocity, temperature, relative humidity, and pressure altitude; complete atmospheric surface turbulent flux measurements for comparison to bulk formulas using standard meteorological observations; boundary layer velocity profile measurements using W-band Doppler radar and high-resolution Doppler lidar; continuous C-band Doppler radar scans measuring radial velocity and radar reflectivity; particle size distributions and chemical composition of aerosols; upper-ocean current
soundings (eight per day) of velocity, temperature, relative humidity, and pressure altitude; complete atmospheric surface turbulent flux measurements for comparison to bulk formulas using standard meteorological observations; boundary layer velocity profile measurements using W-band Doppler radar and high-resolution Doppler lidar; continuous C-band Doppler radar scans measuring radial velocity and radar reflectivity; particle size distributions and chemical composition of aerosols; upper-ocean current
