Bifrost®: Flooding in Earth and Related Environmental Sciences

v. dev (e08ad659)

Niemi, Kristian. (2026, 6 March). Bifrost®-analysis: Flooding in Earth and Related Environmental Sciences. Karlstad University. https://bifrost.kau.se/forskning/miljo/flooding_in_earth_and_related_environmental_sciences.html

1 160
2026*: 1
941
81% av totalt 2026*: 100%
38%
2026*: 100%
+5.1%
Average annual growth rate: 1935–2025
31%
2026*: 0%
1092
2026*: 1
*Year may be incomplete
About key indicators

Key indicators summarise the report’s central metrics. All values are calculated from the underlying dataset and refer to the full period unless otherwise stated. Percentages (peer-reviewed, Open Access, international collaboration) are calculated as a share of total publications per year.

Percentage change is not shown when the base value is below 10 units, as small base values produce statistically unstable percentages (Hicks et al., 2015, principle 8; cf. CDC rule for n < 16). Absolute values are shown instead.

The period 1935–2026 comprises 1 160 publications from 5 145 researchers (SwePub). Two parallel trends are evident: a shift toward peer review and a transition to open access publishing. The share of publications in Level 2 channels (Norwegian list) has decreased during the period.

Följande sökfråga användes:
hsv:(Earth and Related Environmental Sciences) AND ((flooding) OR (flood) OR (översvämning))
Primary data source: SwePub
Enrichment sources: OpenAlex, Kanalregisteret (HK-dir)
Data quality: remarks
Ämneskategorier

Utforska vilka ämneskategorier som finns representerade i datasetet. Notera att publikationer som regel har flera kategorier. Därför är det regel, inte undantag, att procentsatserna tillsammans utgör mer än 100%. Om x är 100% och y är 15% så betyder det att samtliga publikationer kategoriserats som x, och av dem har 15% också kategoriserats som y.

Natural Sciences (81%)
Dominant category
6
Subject areas (level 1)
0.39 / 1.00
Subject diversity (evenness)

Insights
Natural sciences dominates (82 %). Subject breadth has increased — research has become more diversified (1935–2026, H: 0.57 → 0.76). Moderate interdisciplinarity — research combines related subject areas. Rao-Stirling: 0.547 (where 0 = single discipline, 1 = maximum diversity). Based on 6 HSV main areas (Swedish classification).

Method: diversity indices

Shannon H (evenness index) measures how evenly publications are distributed across subject areas. A value of 1.00 means perfect evenness; lower values indicate dominance by individual areas. Rao-Stirling measures interdisciplinarity by weighing both the distribution and the taxonomic distance between subject areas according to the Swedish classification system. The scale ranges from 0 (all publications in one subject) to 1 (maximum spread across distant subject areas).

Nivå 1
Proportionell vy

Andel av totala publikationer per år (%). Notera att en publikation kan tillhöra flera kategorier.

Frekvens av kategori per år
Nivå 2

I datasetet finns det totalt 30 nivå 2-kategorier. Här visas de vanligaste 25.

Proportionell vy

Andel av totala publikationer per år (%). Notera att en publikation kan tillhöra flera kategorier.

Ämneskategorier nivå 2 (tabell)
Nivå 3

During 1935–2026, 18.4% (214 of 1,160) publications lack subject classification at this level.

Proportionell vy

Andel av totala publikationer per år (%). Notera att en publikation kan tillhöra flera kategorier.

Frekvens av kategori per år
Publikationstyper
Antal vetenskapliga publikationer per typ över år
81%
Peer-reviewed
2026: 100%
100%
Scientific
2026: 100%
447
Unique journals
2026: 1
30%
Level 2 (Norwegian list)
249 of 817 classified

Insights
The peer-reviewed share: 86.1 % recent decade (2017–2026), up from 81.5 % previous decade (2007–2016). Long-term trend (1935–2026): increasing. Note that 0% in the first year of the period may reflect incomplete metadata rather than an actual absence of peer review.

1156 publications (100%) scientific, 4 publications (0%) other.

Older years (1935–2018) aggregated for readability. Full timespan available in data export.

Publication types over time
Proportional view
Tidskrifter: refereegranskat och övrigt vetenskapligt
Missing match in the Channel Register (HK-dir). Common causes: missing ISSN in source data, channels outside the register, conference series, or recently launched journals. Lack of classification does not necessarily mean the journal lacks peer review.
Tidskrifter: populärvetenskap, debatt etc
Forskare

Researchers are listed below, sorted by scientific productivity.

5 145
Unique researchers
2026: 5
5%
Top 10 researchers’ publication share
The 10 most productive (of 5 145 total) researchers’ share of all publications
6.0
Co-authors/pub.
2026: 5.0

Insights
The top 20% most productive researchers account for 29% of publications (Gini 0.11, scale: 0 = even, 1 = fully concentrated). Average number of co-authors: 7.4 recent decade (2017–2026), up from 4.6 (2007–2016).

Open Access
38%
Open Access
2026: 100%
6%
Green OA
1935–2026

The OA analysis is based on 840 publications with DOI matched against OpenAlex (72% of 1160 total). 265 publications lack DOI and are therefore not included in OA statistics.

Open Access category definitions
  • Gold OA: Published in a fully open access journal (typically with an article processing charge).
  • Green OA: Freely available via an open repository (e.g. institutional repository), typically after an embargo period of 6–12 months, even if the journal is not open access.
  • Hybrid: Published as an open article in an otherwise subscription-based journal (typically with an APC).
  • Bronze: Freely readable on the publisher’s website but without a clear open license (may be removed).
  • Diamond: Published in a journal that is fully open with no author-facing charges (APC). Often funded by institutions or organizations.
  • Closed: Not freely available — requires subscription or purchase.

Insights
The OA share went from 0 % to 100 % (+100 percentage points) during 1992–2026. Gold accounted for the largest increase (+26.9 percentage points). Green OA accounts for 6 % of all publications — available via open repository after an embargo period (typically 6–12 months); more recent publications may not yet be freely accessible. Diamond OA (no fees for authors or readers) accounts for 3.5 %.

Proportional distribution of Open Access over time
Open Access types over time
Open/closed per year (absolute)
OA types per year (proportional)

Note:
840 of 895 publications with DOI were matched against OpenAlex and assigned OA status (93.9%). OA status is sourced from OpenAlex (based on Unpaywall). OA status may be retroactively classified.

Publications by NPI level

The Norwegian Publication Indicator (NPI), also known as the Norwegian list, classifies publication channels into two levels. Level 2 (top ~20% per field) is considered the most prestigious channels. Level 1 covers other approved channels.

NPI level is a static classification based on the latest available data from the Channel Register (HK-dir). Historical level changes are not considered. Level 2 means the channel belongs to the top ~20% within its field — not that each individual article is necessarily of higher quality (cf. Leiden Manifesto, principle 5).

30.5%
Level 2
2026: 0.0%
249
Level 2 (Count)
2026: 0
545
Level 1 (Count)
2026: 1
343
Unclassified
29.6% of total
A high proportion of publications (≥10%) lack NPI classification. Common causes: missing ISSN in source data, channels outside the register (~40,000 journals), conference series, or recently launched journals. See the journal table for unclassified channels.
NPI level by year
Publications without NPI classification
Samförfattarskap

Insights
101 research groups of roughly equal size; no single cluster dominates. Each researcher collaborates with an average of 5.1 others (a densely connected network). Clear cluster structure (Modularity 0.98); researchers primarily work within their own group. The network is sparse: only 0.8% of all researcher pairs have a direct collaboration link.

Methodology

The co-authorship network is built from co-authored publications. Each node represents a researcher, and each edge is weighted by number of joint publications. Edge weights are normalized using association strength (Van Eck & Waltman, 2009) before clustering with the Louvain algorithm. Centrality measures: degree (number of collaborators), collaboration intensity (total co-authoring frequency), and bridge score (weighted betweenness using inverse weights, Newman 2004). Network density measures the proportion of realized vs. possible collaborations. Terminology: «Collaborators (avg)» = mean degree; «Clustering» = modularity (Newman, 2004).

5.1
Collaborators (avg)
1935–2026
0.98
Clustering
1935–2026
Degree distribution
Sammanfattning
Individuell nätverksstatistik

‘Samförfattade texter’ anger antalet texter författaren skrivit tillsammans med en eller flera samförfattare.

Network statistics show central nodes in the collaboration network. Degree is the number of direct collaborations, while betweenness shows which authors act as bridges between different groups.

Notera: Degree shows the number of unique collaboration partners with SwePub-ID. Authors whose co-authors lack SwePub-ID have no network values.

Vanligaste samförfattarskap

Den första medförfattaren som listas är den som författaren skrivit tillsammans med flest gånger. ‘Antal’ anger antal medförfattade texter med författaren. Upp till fyra ytterligare medförfattare anges, i fallande ordning efter antal medförfattarskap.

Notera: 1991 samarbeten med författare utan SwePub-ID filtrerades bort (ej visade i tabellen)

Nätverk av medförfattare

Nedan är en visualisering av datasetets 101 olika grupperingar. Färgerna anger olika grupper.

The co-authorship network comprises 675 researchers and 1728 collaborations. Due to the size of the dataset, a simplified version highlighting the strongest collaboration patterns (backbone analysis) is shown. Individual connections with few joint publications have been omitted for clarity.

Each node represents a researcher and each link a co-authorship. Colors indicate research groups (clusters) identified via modularity analysis. Node size reflects number of publications.

Gruppmedlemskap

Namn på författare till höger; grupp-id till höger. Du kan se storlek på grupperna och gruppernas vanligaste keywords i tabellerna som följer. En kombination av sökning och sortering kan användas för att utforska gruppmedlemskap vidare.

Gruppstorlek
Keywords för grupper

Tabellen är begränsad till a) grupper med fler än 3 medlemmar; b) grupper med minst ett keyword i någon publikation; c) de tio mest använda nyckelord per grupp.

See also the supervisor and opponent network in the researcher section for an analysis of academic collaboration patterns beyond co-authorship.

Supervisor and opponent network

Unlike the co-authorship analysis, which maps collaboration through joint publications, this section reveals the academic networks that emerge through dissertation supervision and opposition. Supervisors and opponents active at multiple institutions form informal knowledge bridges between organizations — relationships rarely captured by traditional bibliometric measures but which can reveal important patterns in academic knowledge transfer.

The supervisor/opponent network is separate from the international collaboration map. The map is based on co-authorship between author affiliations, while supervisor/opponent relations are shown in the network below.

Insights
37 researchers have supervised or opposed across institutional boundaries. Strongest connection: KTH Royal Institute of Technology – Kungl. Tekniska högskolan (Connection strength: 10). Based on 69.8% of dissertations with identifiable supervisors.

Supervisions  Oppositions
Supervisor and opponent network, figure
Supervisor and opponent network, table

Rangordningen är inte tillförlitlig på grund av ofullständig data. Listan visas i alfabetisk ordning.

Method description

The network is based on supervisor and opponent relationships extracted from SwePub records. Connection strength is calculated as (number of supervisions × 2) + (number of oppositions × 1). The weighting (2:1) is a Bifrost convention reflecting that supervision is a longer and deeper collaborative relationship than opposition. The method lacks established bibliometric practice — it was developed specifically for Bifrost.

The supervisor:opponent weighting (2:1) is a Bifrost convention to reflect the supervisor’s greater role in the dissertation process — this is not established bibliometric practice.

Högskolor och universitet
258
Institutions
36%
Top-3 share

Insights
766 institutions contribute. Uppsala University, Stockholm University and Swedish University for Agricultural Sciences account for 23 % — a broad distribution.

Nyckelord
HSV-ämneskategorier har filtrerats bort från keywords

geovetenskap; remote sensing; learning; miljökemi; mathematics; skogsskötsel; geoteknik; fiske; design (overall design); skogsteknik; fjärranalys; lantmäteri; vatten i natur och samhälle; exogen geovetenskap; atmosfärs- och hydrosfärsvetenskap; övrig geovetenskap; geovetenskap(ersätts med naturgeografi); medicin; miljöteknik; lärande; morfologi

3 226
Unique keywords
climate change (6.8%)
Top keyword

Insights
Broad keyword profile — no single term dominates (HHI: 0.0011 — Herfindahl-Hirschman Index, where 0 = perfectly even distribution, 1 = one term dominates entirely). Most common is “climate change” appearing in 6.8 % of publications, across a total of 3226.

Färger indikerar frekvenskvantiler inom detta dataset.

Röd: Högsta frekvens (6.8-5.46%); Blå: Hög frekvens (5.46-4.12%); Grön: Medelhög frekvens (4.12-2.78%); Orange: Låg frekvens (2.78-1.44%); Grå: Lägsta frekvens (1.44-0.1%)

Nyckelordstrender
Nyckelordsinsikter
Declining themes
Historical Trends

The following keywords had periods of high activity in the past but have since declined. The analysis shows when they peaked, what drove the interest, and how activity has evolved since.

earth sciences: historical trend (2006–2011)

Burst period: 2006–2011 (moderate burst)

Peak year: 2007 (9 pubs.)

Driving actors during period:

  • Researchers: Beven, Keith J. (5 pubs.), Morad, Sadoon (4 pubs.), Beven, Keith J (3 pubs.)
  • Institutions: Uppsala University (33 pubs.), Stockholm University (16 pubs.), Swedish University for Agricultural Sciences (7 pubs.)

Co-varying keywords: uncertainty, flood risk, sequence stratigraphy

Current status: Declining

applied geology: historical trend (1999–2001)

Burst period: 1999–2001 (moderate burst)

Peak year: 2000 (5 pubs.)

Driving actors during period:

  • Researchers: Öhlander, Björn (5 pubs.), Holmström, Henning (4 pubs.), Ingri, Johan (3 pubs.)
  • Institutions: Luleå University of Technology (17 pubs.), California Institute of Technology (2 pubs.), Lund University (2 pubs.)

Co-varying keywords: tillämpad geologi, electron micoprobe analysis, flooding

Current status: Declining

floods: historical trend (2016–2021)

Burst period: 2016–2021 (moderate burst)

Peak year: 2020 (8 pubs.)

Driving actors during period:

  • Researchers: Di Baldassarre, Giuliano (3 pubs.), Halldin, Sven (3 pubs.), Mazzoleni, Maurizio (3 pubs.)
  • Institutions: Uppsala University (36 pubs.), Stockholm University (7 pubs.), University of Gothenburg (7 pubs.)

Co-varying keywords: droughts, hydrology, climate change

Current status: Stable

the changing earth: historical trend (2016–2020)

Burst period: 2016–2020 (moderate burst)

Peak year: 2017 (7 pubs.)

Driving actors during period:

  • Researchers: Andersson, Per S. (3 pubs.), Kutscher, Liselott (3 pubs.), Maximov, Trofim (3 pubs.)
  • Institutions: Stockholm University (12 pubs.), Curtin University (7 pubs.), Lund University (5 pubs.)

Co-varying keywords: den föränderliga jorden, lena river, amphibole microchemistry

Current status: Stable

den föränderliga jorden: historical trend (2016–2020)

Burst period: 2016–2020 (moderate burst)

Peak year: 2017 (5 pubs.)

Driving actors during period:

  • Researchers: Andersson, Per S. (2 pubs.), Kutscher, Liselott (2 pubs.), Maximov, Trofim (2 pubs.)
  • Institutions: Curtin University (7 pubs.), Stockholm University (6 pubs.), Lund University (5 pubs.)

Co-varying keywords: the changing earth, lena river, apollo 14

Current status: Stable

Samförekomst av nyckelord

Heatmappen visar hur ofta nyckelord förekommer tillsammans i samma publikationer. Szymkiewicz-Simpson-koefficienten (0-1) mäter överlappningen mellan två nyckelord i förhållande till det minst frekventa ordets förekomst. Röda asterisker () i rutornas övre högra hörn markerar statistiskt signifikanta samförekomster (p < 0.05).

Mest samförekommande nyckelordspar
Network diagram, keywords

Keywords that frequently co-occur in the same publications form thematic clusters. The table below summarizes the clusters; the interactive graph shows the relationships visually.

The network diagram shows how keywords relate to each other based on co-occurrence in publications. Larger nodes mean more frequent keywords. Lines show co-occurrence. Colors indicate thematic clusters (Leiden algorithm).
Ordfrekvens

Frekvensen av enskilda ord i datasetet som helhet. Ord har hämtats från titel, abstract och keywords. “Frekvens” är totala användningar, inklusive antal omnämningar i en och samma text, medan “publikationer” är antalet unika texter var ordet förekommer.

19 597
Unique words
flood (71.2%)
Top word

Insights
The 5 most common words (by share of publications) are: “flood” (71%), “water” (45%), “flooding” (38%), “climate” (35%), “risk” (30%). These patterns reflect the thematic core of the dataset.

Word frequency table

Notis: Datasetet innehåller 19597 rader. För bästa prestanda visas endast de 8000 med högst frekvens i tabellen.

Ifall du vill undersöka frevkensen av några särskilda ord mer noggrant, ange dem i variabeln ‘to_stem’.

Word Frequency Trends

These trends are indicative and complement the keyword analysis above.

Methodological note: Word frequency analysis is based on individual words extracted from title, abstract, and keywords. Unlike author-selected keywords, individual words can be noisier and more ambiguous — for example, the word ‘system’ may appear in both technical and social science contexts, while the keyword ‘adaptive systems’ is more precise. Stricter thresholds are used (minimum 10 occurrences, correlation > 0.5) and academic stopwords are excluded.

Rising/declining shows trends over time (Spearman correlation). New/disappearing shows lifecycle — when words started or stopped being used.

Rising words: adaptation, additionally, assessment, blue, climate, coastal, consequences, dense, disaster, drought

…and 36 more words

Declining words: 0.2, 0.5, 2d, abrupt, absence, abundant, acceptable, accounted, accounts, accumulated

…and 825 more words

New words (first seen 2005 or later): 0.1, 0.3, 2.5, 2d, 3d, 4.5, 8.5, ability, abrupt, absence

…and 1037 more words

Analyzed 2042 words (minimum 10 occurrences, minimum 5 years).

Avhandlingar

The first doctoral thesis in the dataset is from 1935, Studies of the morphological activity of rivers as illustrated by the River Fyris by Hjulström, Filip. From then until 2025, a total of 83 theses have been registered. Of these, 70 are doctoral theses and 13 are licentiate theses.

83
Avhandlingar
2026: 0
Handledare
Opponenter
Publikationer

En komplett lista av sökningens resultat. Initialt sorterat efter år (fallande) och författare (stigande). Ändra ordningen vid kolumnrubriken. Sökning kan göras över alla visade fält.