R/V Mirai Cruise Report MR15-04 The observational study of the heavy rainfall zone in the eastern Indian Ocean Eastern Indian Ocean “Maritime Continent” November 5, 2015 – December 20, 2015 Japan Agency for Agency for the Assessment Marine-Earth Science and and Application of Technology Technology JAMSTEC, Japan BPPT, Indonesia MR15-04 Cruise Report --- Contents --- 1 Introduction 2 Cruise summary 3 Cruise track and log 4 List of participants 5 Summary of observations 5.1 GPS radiosonde 5.2 GNSS precipitable water 5.3 C-band weather radar 5.4 Ka-band radar 5.5 Micro rain radar 5.6 Disdrometers 5.7 Videosonde 5.8 Lidar 5.9 Ceilometer 5.10 Shipborne sky radiometer 5.11 Aerosol and gas observations 5.12 Greenhouse gas observations 5.13 Surface meteorological observations 5.14 Continuous monitoring of surface seawater 5.15 Underway pCO2 5.16 CTDO profiling 5.17 Salinity of sampled water 5.18 Dissolved oxygen of sampled water 5.19 Nutrients of sampled water 5.20 Chlorophyll a of sampled water 5.21 HPLC 5.22 LADCP 5.23 Microstructure profiler (MSP) for the ocean 5.24 Underway CTD 5.25 XCTD 5.26 Wave Glider 5.27 Testing CTD sensor for the new floats 5.28 Distribution, cool- and heat-tolerances of the oceanic sea skaters of Halobates 5.29 Underway geophysics Appendices A. Atmospheric profiles by the radiosonde observations B. Oceanic profiles by the CTDO observations 1. Introduction The maritime continent (MC) is a key region in the global weather and climate. For example, vital convective activity over MC is a driving force for the global atmospheric circulation. The convective activity over MC is well known to be regulated largely by diurnal cycle, intra-seasonal variations (e.g. Madden-Julian Oscillation (MJO)), seasonal variations (e.g. Asia-Australia monsoon), and inter-annual variations (e.g. El Nino / Southern Oscillation (ENSO)). Among them, for example, the different diurnal characteristics between over landmass and over adjacent seas are still not well reproduced even by the state-of-the-art atmospheric numerical models. The eastward penetration of the MJO over MC from Indian Ocean to the western Pacific is also the big issue to be improved in the numerical models. The deficiencies to understand and to reproduce these variations are considered to be caused by the lack of our knowledge on, for example, the localized mesoscale circulations associated with coastlines and topography, and /or the moist convection processes over the region. To improve our understandings on these processes in the MC region, the fine-scale, multi-disciplinary observational data is desired. In the past, many projects have been tried to obtain the observational evidence to reveal the nature of these processes over the MC. While these projects (e.g. CPEA1, JEPP-HARIMAU2) revealed the nature of the convections over the land and coast in the various situations, the ocean-atmosphere processes in the adjacent sea is still remained to be investigated. To reveal the oceanic and atmospheric processes in the MC, the collaborative team lead by Japan-Agency of Marine-Earth Science and Technology (JAMSTEC), Indonesian Agency for the Assessment and Application of Technology (Badan Pengkajian dan Penerapan Teknology, BPPT), and Indonesian Agency for Meteorlogy, Climatology and Geophysica (Badan Meteorologi, Klimatologi dan Geofisika, BMKG) planned to deploy the observation network off the western Sumatra, which consists of the research vessel (R/V) Mirai, (which equips bunch of observational instruments like C-band polarimetric radar, CTD system, radiosonde launcher, etc.) and the land-based sites near Bengkulu (with weather radars, radiosonde observations, special “videosonde” observations, and so on) to contrast the processes over land and ocean. We set the target area as the ocean near Bengkulu, western Sumatra, with considering the following factors: (1) The satellite measurements (e.g. TRMM products) tell the heavy oceanic rainfall occurs near the coast in the area. (2) The coastline is rather straight, where the two-dimensional processes orthogonal to the coastline can be assumed to simplify the background to understand the coastal process, with our limited observational resources. (3) The small islands off the coast (like in, for example, the near-equator of the western Sumatra), which may disturb the assumption in (2) and hinder the principles we are trying to reveal, are sparse. (4) The coastline elongated with certain angle (not near-parallel) to the zonal wind which dominate the wind component in the equatorial region (to encourage understanding quasi two-dimensional processes) This cruise report summarizes the observed items and preliminary results during the R/V Mirai MR15-04 cruise. The cruise consists of three parts. The primary part is the stationary observation off Bengkulu, west of 1 Coupled Process of the Equatorial Atmosphere 2 Japan EOS (Earth Observation System) Promotion Plan (JEPP) Hydro-meteorological Array for ISV-Monsoon Auto-monitoring. 1-1 Sumatra Island to obtain continuous, fine temporal-resolution data for both atmospheric and oceanic states. The principle component of the observations are the surface meteorological measurement, atmospheric sounding by radiosonde, CTD and LADCP casting to profile the ocean thermodynamic and dynamic status, as well as the C-band polarimetric radar observation to capture the details of precipitating systems. Before and after the stationary observation period, the oceanic cross sections along the line between (6S, 101E) and (4S, 102E), namely quasi-orthogonal to the coastline, were obtained by CTD or UCTD observations. Oceanic cross sections were obtained also at the Makassar and Lombok straights by utilizing UCTD and XCTD. In addition, the continuous observations by the autonomous / underway instruments were carried out along the track to / from the stationary observation point. In this report, the first several sections describes the basic information such as cruise track, on board personnel list are described. Details of each observation are described in Section 5. Additional information and figures are also attached as Appendices. *** Remarks *** This cruise report is a preliminary documentation as of the end of the cruise. The contents may be not updated after the end of the cruise, while the contents may be subject to change without notice. Data on the cruise report may be raw or not processed. Please ask the Chief Scientist and the Principle Investigators for the latest information. 1-2 2. Cruise Summary 2.1 Ship Name Research Vessel MIRAI L x B x D 128.6m x 19.0m x 13.2m Gross Tonnage 8,706 tons Call Sign JNSR Home Port Mutsu, Aomori Prefecture, Japan 2.2 Cruise Code MR15-04 2.3 Project Name (Main mission) “The observational study of the heavy rainfall zone in the eastern Indian Ocean”, (as a part of the Japan-Indonesia collaborative research project “Observational studies of heavy precipitation caused by air-sea interaction in and around coast of western Sumatra water and intra to inter-decadal climate variability of oceanographic environment in the eastern Indian Ocean off Java”) 2.4 Undertaking Institute Japan Agency for Marine-Earth Science and Technology (JAMSTEC) 2-15, Natsushima, Yokosuka, Kanagawa 237-0061, JAPAN Agency for Assessment and Application of Technology (BPPT) Jalan Mohammad Hunsni Thamrin 8, Jakarta 10340, INDONESIA 2.5 Chief Scientist Masaki KATSUMATA Tropical Climate Variability Research Program, Research Institute for Global Change, JAMSTEC Dedy Swandry Banurea Agency for Meteorology, Climatorlogy and Geophysics (BMKG) 2.6 Representative of the science party [Affiliation] Kunio Yoneyama [JAMSTEC] 2.7 Periods and Ports of Call Nov. 5: departed Sekinehama, Japan Nov. 6: called Hachinohe, Japan Dec. 20: arrived Jakarta, Indonesia 2.8 Research Themes of Sub-missions and Principal Investigators (PIs) (1) Observational study on clouds and mixed layer depths over the tropical ocean (PI: Kazuaki YASUNAGA / Toyama University) (2) Researches on the organized precipitation systems and the roles of their accompanying cold pool over the eastern Indian Ocean (PI: Hiroaki MIURA / University of Tokyo) (3) Physiological and ecological studies on the relationship between the distribution and salinity and temperature tolerance, and environmental factors in oceanic sea skaters, Halobates, inhabiting eastern tropical Indian Ocean (PI: Tetsuo HARADA / Kochi University) 2-1 (4) Advanced measurements of aerosols in the marine atmosphere: Toward elucidation of interactions with climate and ecosystem (PI: Yugo KANAYA / JAMSTEC) (5) Videosonde observations of ice particles in the precipitating clouds developed over the tropical ocean (PI: Kenji SUZUKI / Yamaguchi University) (6) Aerosol optical characteristics measured by ship-borne sky radiometer (PI: Kazuma AOKI / Toyama University) (7) Shipboard CO2 observations over the tropical Indo-Pacific Ocean for a simple estimation fo the carbon flux between the ocean and the atmosphere from GOSAT data (PI: Kei SHIOMI / Japan Aerospace Exploration Agency (JAXA)) 2.9 Observation Summary GPS Radiosonde 224 times Nov. 11 to Dec. 18 GNSS water vapor observation continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 C-band Doppler radar continuously Nov. 8 to Nov. 13 / Nov. 15 to Dec. 19 Micro rain radar continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 Disdrometers continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 Videosonde 5 times Nov. 29 to Dec. 15 Lidar continuously Nov. 12 to Nov. 13/ Nov.15 to Dec. 19 Ceilometer continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 Sky Radiometer continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 Aerosol and gas observations continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 Greenhouse gas observations continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 Surface Meteorology continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 20 Sea surface water monitoring continuously Nov. 5 to Nov. 13 / Nov. 15 to Dec. 19 pCO2 observations continuously Nov. 8 to Nov. 13 CTDO profiling 221 profiles Nov.