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Hajime Obata

Hajime Obata

D-Index & Metrics

Discipline name D-Index World Ranking Current World Ranking National Ranking Current National Ranking Publications Citations
Earth Science 42 5348 4944 139 128 185 5588

Hajime Obata publications per year

The chart shows the history of publications by Hajime Obata between 1981 and 2025, highlighting the no. of papers published in each year and offering an overview of the publication velocity of this scholar. Hajime Obata published across 45 years, from 1981 to 2025, averaging 5 papers a year. Output peaked at 16 publications in 2019. 23 of the 224 publications appeared in the last two years.

No. of publications
5 10 15
Bar chart. Horizontal axis: year, 1981 to 2025. Vertical axis: number of publications, 0 to 16. Peak 16 publications in 2019. 1981: 3 publications 1982: 0 publications 1983: 0 publications 1984: 0 publications 1985: 0 publications 1986: 0 publications 1987: 0 publications 1988: 0 publications 1989: 0 publications 1990: 0 publications 1991: 0 publications 1992: 0 publications 1993: 1 publication 1994: 0 publications 1995: 2 publications 1996: 2 publications 1997: 1 publication 1998: 2 publications 1999: 0 publications 2000: 5 publications 2001: 4 publications 2002: 2 publications 2003: 4 publications 2004: 6 publications 2005: 1 publication 2006: 3 publications 2007: 13 publications 2008: 7 publications 2009: 10 publications 2010: 9 publications 2011: 4 publications 2012: 1 publication 2013: 8 publications 2014: 10 publications 2015: 9 publications 2016: 12 publications 2017: 12 publications 2018: 12 publications 2019: 16 publications 2020: 11 publications 2021: 16 publications 2022: 8 publications 2023: 7 publications 2024: 13 publications 2025: 10 publications
1981 2025

224 publications in total across all disciplines

View publications per year as a table
Hajime Obata: publications per year, 1981 to 2025
Year Publications
1981 3
1982 0
1983 0
1984 0
1985 0
1986 0
1987 0
1988 0
1989 0
1990 0
1991 0
1992 0
1993 1
1994 0
1995 2
1996 2
1997 1
1998 2
1999 0
2000 5
2001 4
2002 2
2003 4
2004 6
2005 1
2006 3
2007 13
2008 7
2009 10
2010 9
2011 4
2012 1
2013 8
2014 10
2015 9
2016 12
2017 12
2018 12
2019 16
2020 11
2021 16
2022 8
2023 7
2024 13
2025 10
Total 224
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Hajime Obata publication distribution in Earth Science in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Earth Science in 2026. The highlighted bar marks where Hajime Obata sits on this spectrum.

No. of scientists
100 200 300 400 500
Bar chart with 58 bars. Horizontal axis: publications, 38–47 to 603+. Vertical axis: number of scientists, 0 to 557. Most scientists, 557, have 128–137 publications. The last bar groups every scientist with 603 publications or more. The highlighted bar, 178–187 publications, is where this scientist sits. 38–47 publications: 5 scientists 48–57 publications: 33 scientists 58–67 publications: 94 scientists 68–77 publications: 161 scientists 78–87 publications: 278 scientists 88–97 publications: 376 scientists 98–107 publications: 404 scientists 108–117 publications: 484 scientists 118–127 publications: 540 scientists 128–137 publications: 557 scientists 138–147 publications: 491 scientists 148–157 publications: 495 scientists 158–167 publications: 458 scientists 168–177 publications: 490 scientists 178–187 publications: 414 scientists 188–197 publications: 401 scientists 198–207 publications: 333 scientists 208–217 publications: 292 scientists 218–227 publications: 290 scientists 228–237 publications: 262 scientists 238–247 publications: 243 scientists 248–257 publications: 208 scientists 258–267 publications: 185 scientists 268–277 publications: 147 scientists 278–287 publications: 128 scientists 288–297 publications: 119 scientists 298–307 publications: 120 scientists 308–317 publications: 107 scientists 318–327 publications: 93 scientists 328–337 publications: 87 scientists 338–347 publications: 64 scientists 348–357 publications: 87 scientists 358–367 publications: 60 scientists 368–377 publications: 60 scientists 378–387 publications: 34 scientists 388–397 publications: 50 scientists 398–407 publications: 44 scientists 408–417 publications: 31 scientists 418–427 publications: 39 scientists 428–437 publications: 27 scientists 438–447 publications: 36 scientists 448–457 publications: 27 scientists 458–467 publications: 29 scientists 468–477 publications: 30 scientists 478–487 publications: 19 scientists 488–497 publications: 15 scientists 498–507 publications: 18 scientists 508–517 publications: 19 scientists 518–527 publications: 16 scientists 528–537 publications: 10 scientists 538–547 publications: 11 scientists 548–557 publications: 14 scientists 558–567 publications: 11 scientists 568–577 publications: 7 scientists 578–587 publications: 14 scientists 588–597 publications: 5 scientists 598–602 publications: 4 scientists 603+ publications: 100 scientists
38–47 publications 603+

This scientist: 185 publications — 57th percentile

57% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 603 publications or more.

View publications distribution as a table
Number of Earth Science scientists by publication count, Research.com 2026 ranking edition. Based on 9,176 ranked scientists.
Publications Scientists This scientist
38–47 5
48–57 33
58–67 94
68–77 161
78–87 278
88–97 376
98–107 404
108–117 484
118–127 540
128–137 557
138–147 491
148–157 495
158–167 458
168–177 490
178–187 414 185
188–197 401
198–207 333
208–217 292
218–227 290
228–237 262
238–247 243
248–257 208
258–267 185
268–277 147
278–287 128
288–297 119
298–307 120
308–317 107
318–327 93
328–337 87
338–347 64
348–357 87
358–367 60
368–377 60
378–387 34
388–397 50
398–407 44
408–417 31
418–427 39
428–437 27
438–447 36
448–457 27
458–467 29
468–477 30
478–487 19
488–497 15
498–507 18
508–517 19
518–527 16
528–537 10
538–547 11
548–557 14
558–567 11
568–577 7
578–587 14
588–597 5
598–602 4
603+ 100
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Hajime Obata D-index placement in Earth Science in 2026

The chart shows the D-index (discipline H-index) distribution of Earth Science scientists ranked by Research.com in 2026. The highlighted bar marks where Hajime Obata sits on this spectrum.

No. of scientists
100 200 300
Bar chart with 77 bars. Horizontal axis: D-Index, 30 to 106+. Vertical axis: number of scientists, 0 to 389. Most scientists, 389, have 36 D-Index. The last bar groups every scientist with 106 D-Index or more. The highlighted bar, 42 D-Index, is where this scientist sits. 30 D-Index: 144 scientists 31 D-Index: 215 scientists 32 D-Index: 278 scientists 33 D-Index: 379 scientists 34 D-Index: 366 scientists 35 D-Index: 372 scientists 36 D-Index: 389 scientists 37 D-Index: 366 scientists 38 D-Index: 344 scientists 39 D-Index: 349 scientists 40 D-Index: 296 scientists 41 D-Index: 289 scientists 42 D-Index: 277 scientists 43 D-Index: 279 scientists 44 D-Index: 248 scientists 45 D-Index: 257 scientists 46 D-Index: 212 scientists 47 D-Index: 202 scientists 48 D-Index: 207 scientists 49 D-Index: 204 scientists 50 D-Index: 183 scientists 51 D-Index: 178 scientists 52 D-Index: 182 scientists 53 D-Index: 178 scientists 54 D-Index: 163 scientists 55 D-Index: 117 scientists 56 D-Index: 163 scientists 57 D-Index: 120 scientists 58 D-Index: 113 scientists 59 D-Index: 136 scientists 60 D-Index: 135 scientists 61 D-Index: 96 scientists 62 D-Index: 103 scientists 63 D-Index: 83 scientists 64 D-Index: 103 scientists 65 D-Index: 83 scientists 66 D-Index: 89 scientists 67 D-Index: 92 scientists 68 D-Index: 89 scientists 69 D-Index: 78 scientists 70 D-Index: 75 scientists 71 D-Index: 53 scientists 72 D-Index: 62 scientists 73 D-Index: 54 scientists 74 D-Index: 35 scientists 75 D-Index: 52 scientists 76 D-Index: 50 scientists 77 D-Index: 32 scientists 78 D-Index: 37 scientists 79 D-Index: 20 scientists 80 D-Index: 33 scientists 81 D-Index: 36 scientists 82 D-Index: 34 scientists 83 D-Index: 34 scientists 84 D-Index: 24 scientists 85 D-Index: 19 scientists 86 D-Index: 18 scientists 87 D-Index: 26 scientists 88 D-Index: 30 scientists 89 D-Index: 17 scientists 90 D-Index: 21 scientists 91 D-Index: 19 scientists 92 D-Index: 15 scientists 93 D-Index: 14 scientists 94 D-Index: 20 scientists 95 D-Index: 9 scientists 96 D-Index: 10 scientists 97 D-Index: 15 scientists 98 D-Index: 13 scientists 99 D-Index: 3 scientists 100 D-Index: 13 scientists 101 D-Index: 3 scientists 102 D-Index: 9 scientists 103 D-Index: 4 scientists 104 D-Index: 6 scientists 105 D-Index: 6 scientists 106+ D-Index: 98 scientists
30 D-Index 106+

This scientist: 42 D-Index — 44th percentile

44% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 106 D-Index or more.

View D-Index distribution as a table
Number of Earth Science scientists by D-index, Research.com 2026 ranking edition. Based on 9,176 ranked scientists.
D-Index Scientists This scientist
30 144
31 215
32 278
33 379
34 366
35 372
36 389
37 366
38 344
39 349
40 296
41 289
42 277 42
43 279
44 248
45 257
46 212
47 202
48 207
49 204
50 183
51 178
52 182
53 178
54 163
55 117
56 163
57 120
58 113
59 136
60 135
61 96
62 103
63 83
64 103
65 83
66 89
67 92
68 89
69 78
70 75
71 53
72 62
73 54
74 35
75 52
76 50
77 32
78 37
79 20
80 33
81 36
82 34
83 34
84 24
85 19
86 18
87 26
88 30
89 17
90 21
91 19
92 15
93 14
94 20
95 9
96 10
97 15
98 13
99 3
100 13
101 3
102 9
103 4
104 6
105 6
106+ 98
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Overview

Hajime Obata is affiliated with the University of Tokyo in Japan and has contributed extensively to the fields of Earth and Planetary Sciences and Environmental Science. Their research emphasizes Oceanography, which forms a significant part of their scholarly work, alongside studies in Health, Toxicology and Mutagenesis, Ecology, Environmental Chemistry, and Atmospheric Science.

Their primary research themes include marine and coastal ecosystems, marine biology and ecology research, mercury impact and mitigation studies, methane hydrates and related phenomena, geochemistry and elemental analysis, heavy metals in the environment, and isotope analysis in ecology.

Obata's research outputs are published in various scientific venues, with frequent publications in Marine Chemistry, Journal of Oceanography, Journal of Geophysical Research Oceans, Geochimica et Cosmochimica Acta, and Scientific Reports. These journals reflect the environmental and marine science context of their work.

Recent publications highlight aspects of biogeochemical cycles, ocean nutrient transport, and trace metal dynamics in the North Pacific. Selected recent papers include:

  • "Subpolar marginal seas fuel the North Pacific through the intermediate water at the termination of the global ocean circulation," 2020, Proceedings of the National Academy of Sciences
  • "Shelf humic substances as carriers for basin-scale iron transport in the North Pacific," 2020, Scientific Reports
  • "A review: iron and nutrient supply in the subarctic Pacific and its impact on phytoplankton production," 2021, Journal of Oceanography
  • "Widespread distribution of allochthonous fluorescent dissolved organic matter in the intermediate water of the North Pacific," 2020, Progress In Oceanography
  • "Slowly Sinking Particles Underlie Dissolved Iron Transport Across the Pacific Ocean," 2021, Global Biogeochemical Cycles

Collaboration is notable in Obata's work, with frequent coauthors including Jun Nishioka, Kuo Hong Wong, Hiroshi Ogawa, Asami S. Mashio, and Shigenobu Takeda.

Best Publications

  • Automated determination of iron in seawater by chelating resin concentration and chemiluminescence detection

    Hajime. Obata;Hajime. Karatani;Eiichiro. Nakayama

  • The GEOTRACES Intermediate Data Product 2017

    Reiner Schlitzer;Robert F. Anderson;Elena Masferrer Dodas;Maeve Lohan

  • Developing standards for dissolved iron in seawater

    Kenneth S. Johnson;Edward Boyle;Kenneth Bruland;Kenneth Coale

  • Sampling and Sample-handling Protocols for GEOTRACES Cruises

    G. Cutter;P. Andersson;Lou Codispoti;P. Croot

  • Evidence of an extensive spread of hydrothermal dissolved iron in the Indian Ocean

    Jun Nishioka;Hajime Obata;Daisuke Tsumune

  • Hydrothermal fluid geochemistry at the Iheya North field in the mid-Okinawa trough: Implication for origin of methane in subseafloor fluid circulation systems

    Shinsuke Kawagucci;Shinsuke Kawagucci;Hitoshi Chiba;Jun Ichiro Ishibashi;Toshiro Yamanaka

  • Colorimetric Detection of Mercury(II) Ion in Aqueous Solution Using Silver Nanoparticles

    M. Lutfi Firdaus;Ikka Fitriani;Santhy Wyantuti;Yeni W. Hartati

  • Determination of trace elements in seawater by fluorinated metal alkoxide glass-immobilized 8-hydroxyquinoline concentration and high-resolution inductively coupled plasma mass spectrometry detection

    Yoshiki Sohrin;Shun-ichi Iwamoto;Shoji Akiyama;Takeshi Fujita

  • The GEOTRACES Intermediate Data Product 2014

    Edward Mawji;Reiner Schlitzer;Elena Masferrer Dodas;Cyril Abadie

  • Anthropogenic Lead Emissions in the Ocean: The Evolving Global Experiment

    Jong-Mi Lee;Yolanda Echegoyen;Gonzalo Carrasco;Ning Zhao

  • Evidence for the grazing hypothesis: Grazing reduces phytoplankton responses of the HNLC ecosystem to iron enrichment in the western subarctic pacific (SEEDS II)

    Atsushi Tsuda;Shigenobu Takeda;Hiroaki Saito;Jun Nishioka

  • Subpolar marginal seas fuel the North Pacific through the intermediate water at the termination of the global ocean circulation.

    Jun Nishioka;Hajime Obata;Hiroshi Ogawa;Kazuya Ono

  • Geochemical origin of hydrothermal fluid methane in sediment-associated fields and its relevance to the geographical distribution of whole hydrothermal circulation

    Shinsuke Kawagucci;Shinsuke Kawagucci;Yuichiro Ueno;Yuichiro Ueno;Ken Takai;Tomohiro Toki

  • Response of equatorial Pacific phytoplankton to subnanomolar Fe enrichment

    Shigenobu Takeda;Hajime Obata

  • Hydrothermal impacts on trace element and isotope ocean biogeochemistry

    Christopher R. German;Karen L. Casciotti;Jean-Claude Dutay;Lars-Eric Heimburger

  • Eastߞwest gradients in the photosynthetic potential of phytoplankton and iron concentration in the subarctic Pacific Ocean during early summer

    Koji Suzuki;Hongbin Liu;Toshiro Saino;Hajime Obata

  • The distribution of Fe in the Australian sector of the Southern Ocean

    Y. Sohrin;S. Iwamoto;M. Matsui;H. Obata

  • High-resolution measurement of multiple volatile organic compounds dissolved in seawater using equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS)

    Sohiko Kameyama;Hiroshi Tanimoto;Satoshi Inomata;Urumu Tsunogai

  • Hydrothermal plumes at the Rodriguez triple junction, Indian ridge

    Toshitaka Gamo;Eiichiro Nakayama;Kiminori Shitashima;Kenji Isshiki

  • Tritium in Japanese precipitation following the March 2011 Fukushima Daiichi Nuclear Plant accident.

    Takuya Matsumoto;Teruyuki Maruoka;Gen Shimoda;Hajime Obata

  • Development of a deep-sea in situ Mn analyzer and its application for hydrothermal plume observation

    Kei Okamura;Hideshi Kimoto;Kazuyoshi Saeki;Junichiro Ishibashi

  • Dissolved iron distribution in the western and central subarctic Pacific: HNLC water formation and biogeochemical processes

    Jun Nishioka;Hajime Obata

Frequent Co-Authors

Toshitaka Gamo
Toshitaka Gamo University of Tokyo
Jun Nishioka
Jun Nishioka Hokkaido University
Shigenobu Takeda
Shigenobu Takeda Nagasaki University
Yuji Sano
Yuji Sano Kōchi University
Urumu Tsunogai
Urumu Tsunogai Nagoya University
Youhei Yamashita
Youhei Yamashita Hokkaido University
Yoshiyuki Nozaki
Yoshiyuki Nozaki University of Tokyo
Naoto Takahata
Naoto Takahata University of Tokyo
Mitsuo Uematsu
Mitsuo Uematsu University of Tokyo
Yoshiki Sohrin
Yoshiki Sohrin Kyoto University

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