Solar hard UV is weakening.

The EUV spectrum of the Sun: Irradiances during 1998–2014
G. Del Zanna 1 and V. Andretta 2
A&A 584, A29 (2015)
DOI: 10.1051/0004-6361/201526804
(c) ESO 2015
Open access on registration

Examples from paper Fig 6

From abstract

… show that the irradiances in the hot (2–3 MK) lines are significantly
lower for the cycle 24 maximum compared to the previous one.

From Introduction

1. Introduction
The present paper is part of an on-going effort to provide the
best possible solar spectral irradiance in the extreme ultraviolet
(EUV). The solar EUV variability causes dramatic changes in
the temperature and density of the thermosphere, and it could
also have some indirect effects on the climate. Indeed, some of
the current global circulation models also require EUV irradi-
ances to properly take the solar forcing into account.

The work is about correcting for known satellite instrument degradation.

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